Document and Entity Information - shares	6 Months Ended
Document and Entity Information - shares	Jun. 30, 2017	Jul. 24, 2017
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2017
Document Fiscal Year Focus	2017
Document Fiscal Period Focus	Q2
Trading Symbol	IRTC
Entity Registrant Name	iRhythm Technologies, Inc.
Entity Central Index Key	0001388658
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Common Stock, Shares Outstanding		22,729,907

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 16,249	$ 51,643
Investments, short-term	93,578	54,407
Accounts receivable, net	10,851	9,406
Inventory	1,231	1,390
Prepaid expenses and other current assets	1,817	1,671
Restricted cash	91	91
Total current assets	123,817	118,608
Investments, long-term		10,981
Property and equipment, net	6,166	4,653
Goodwill	862	862
Other assets	3,531	3,052
Total assets	134,376	138,156
Current liabilities:
Accounts payable	2,658	2,103
Accrued liabilities	9,985	10,165
Deferred revenue	557	947
Accrued interest, current portion	525
Debt, current portion	1,471
Total current liabilities	15,196	13,215
Debt	31,614	32,227
Deferred rent, noncurrent portion	140	26
Accrued interest, net of current portion		126
Total liabilities	46,950	45,594
Commitments and contingencies (Note 7)
Stockholders’ equity:
Preferred stock, $0.001 par value – 5,000,000 authorized at June 30, 2017 and December 31, 2016, respectively; and none issued and outstanding at June 30, 2017 and December 31, 2016, respectively
Common stock, $0.001 par value – 100,000,000 shares authorized at June 30, 2017 and December 31, 2016, respectively; 22,588,422 and 22,139,346 shares issued and outstanding at June 30, 2017 and December 31, 2016, respectively	27	22
Additional paid-in capital	226,365	219,718
Accumulated other comprehensive loss	(50)	(9)
Accumulated deficit	(138,916)	(127,169)
Total stockholders’ equity	87,426	92,562
Total liabilities and stockholders’ equity	$ 134,376	$ 138,156

Condensed Consolidated Balance Sheets (Parenthetical) (Unaudited) - $ / shares	Jun. 30, 2017	Dec. 31, 2016
Statement Of Financial Position [Abstract]
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	22,588,422	22,139,346
Common stock, shares outstanding	22,588,422	22,139,346

Condensed Consolidated Statements of Operations (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Income Statement [Abstract]
Revenue	$ 23,854	$ 15,734	$ 45,291	$ 28,588
Cost of revenue	6,744	5,156	13,081	9,815
Gross profit	17,110	10,578	32,210	18,773
Operating expenses:
Research and development	2,776	1,667	5,397	3,212
Selling, general and administrative	20,255	12,608	37,479	24,129
Total operating expenses	23,031	14,275	42,876	27,341
Loss from operations	(5,921)	(3,697)	(10,666)	(8,568)
Interest expense	(839)	(803)	(1,661)	(1,581)
Other income (expense), net	316	64	580	(413)
Net loss	$ (6,444)	$ (4,436)	$ (11,747)	$ (10,562)
Net loss per common share, basic and diluted	$ (0.29)	$ (3.09)	$ (0.53)	$ (7.42)
Weighted-average shares used to compute net loss per common share, basic and diluted	22,362,608	1,435,483	22,257,849	1,424,278

Condensed Consolidated Statements of Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Statement Of Income And Comprehensive Income [Abstract]
Net Loss	$ (6,444)	$ (4,436)	$ (11,747)	$ (10,562)
Other comprehensive loss:
Change in unrealized loss on available-for-sale securities	(22)		(41)
Comprehensive loss	$ (6,466)	$ (4,436)	$ (11,788)	$ (10,562)

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Cash flows from operating activities
Net Loss	$ (11,747)	$ (10,562)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	635	436
Stock-based compensation	4,292	850
Amortization of debt discount and issuance costs	128	125
Amortization of premiums (accretion of discounts) on investments, net	(116)
Non-cash interest expense	759	727
Provision for bad debt and contractual allowance	4,216	2,116
Change in fair value of preferred stock warrant liabilities		397
Changes in operating assets and liabilities:
Accounts receivable	(5,662)	(5,768)
Inventory	159	(311)
Prepaid expenses and other current assets	(25)	(17)
Other assets	(508)	(499)
Accounts payable	526	116
Accrued liabilities	219	(827)
Deferred revenue	(390)	(147)
Deferred rent	114
Net cash used in operating activities	(7,400)	(13,364)
Cash flows from investing activities
Purchases of property and equipment	(2,120)	(1,069)
Purchases of available-for-sale investments	(56,034)
Maturities of available-for-sale investments	27,800
Net cash used in investing activities	(30,354)	(1,069)
Cash flows from financing activities
Proceeds from issuance of common stock related to the exercise of options and employee stock purchase program, net of repurchases	2,360	75
Payments of deferred issuance costs		(1,876)
Net cash provided by (used in) financing activities	2,360	(1,801)
Net decrease in cash and cash equivalents	(35,394)	(16,234)
Cash and cash equivalents, beginning of period	51,643	25,208
Cash and cash equivalents, end of period	16,249	8,974
Supplemental disclosures of cash flow information
Interest paid	375	838
Non-cash investing and financing activities
Deferred offering costs included in accounts payable and accrued liabilities		$ 397
Property, plant and equipment costs included in accounts payable	$ 28

Organization and Description of Business	6 Months Ended
Organization and Description of Business	Jun. 30, 2017
Accounting Policies [Abstract]
Organization and Description of Business	1. Organization and Description of Business iRhythm Technologies, Inc. (the “Company”) was incorporated in the state of Delaware in September 2006. The Company is a digital healthcare company redefining the way cardiac arrhythmias are clinically diagnosed by combining wearable biosensing technology with cloud-based data analytics and machine-learning capabilities. The Company commenced commercial introduction of its products in the United States in 2009 following clearance by the U.S. Food and Drug Administration. The Company’s headquarters are based in San Francisco, California, and the Company has manufacturing facilities in Cypress, California, and clinical centers in Lincolnshire, Illinois and Houston, Texas. In March 2016, the Company formed a wholly-owned subsidiary in the United Kingdom. The Company manages its operations as a single operating segment. Substantially all of the Company’s assets are maintained in the United States. The Company derives substantially all of its revenue from sales to customers in the United States, based upon the billing address of the customer. Reverse Stock Split On October 4, 2016, the Company’s board of directors approved an amendment to the Company’s amended and restated certificate of incorporation to effect a reverse split of the Company’s issued and outstanding common stock at a 1-for-5.882698 ratio, which was effected on October 5, 2016. The par value and authorized shares of common stock and convertible preferred stock were not adjusted as a result of the reverse split. All issued and outstanding common stock, options to purchase common stock and per share amounts contained in these condensed consolidated financial statements have been retroactively adjusted to reflect the reverse stock split for all periods presented. Initial Public Offering The Company’s initial public offering (“IPO”) of 7,238,235 shares of common stock was effected through a registration statement on Form S-1 (Registration Nos. 333-213773 and 333-214179), which was declared effective on October 19, 2016. The initial public offering closed on October 25, 2016 and resulted in net proceeds of approximately $110.7 million, after deducting underwriting discounts and commissions of $8.6 million and other expenses of $3.7 million. In October 2016, immediately upon the Company’s sale of its common stock in the initial public offering, all outstanding shares of convertible preferred stock converted into 13,375,333 shares of common stock with the related carrying value of $97.6 million reclassified to common stock and additional paid-in capital. In addition, all convertible preferred stock warrants were also thereby converted into common stock warrants.

Summary of Significant Accounting Policies

6 Months Ended

Jun. 30, 2017

Accounting Policies [Abstract]

Summary of Significant Accounting Policies

2. Summary of Significant Accounting Policies

Basis of Presentation

The accompanying financial statements have been prepared in accordance with generally accepted accounting principles in the United States of America, or U.S. GAAP, and applicable rules and regulations of the Securities and Exchange Commission, or SEC, regarding interim financial reporting. As permitted under those rules, certain footnotes or other financial information that are normally required by GAAP have been condensed or omitted, and accordingly the balance sheet as of December 31, 2016 has been derived from the audited consolidated financial statements at that date but does not include all of the information required by GAAP for complete consolidated financial statements. These unaudited condensed consolidated financial statements have been prepared on the same basis as the Company’s annual consolidated financial statements and, in the opinion of management, reflect all adjustments (consisting only of normal recurring adjustments) that are necessary for the fair statement of the Company’s condensed consolidated financial information. The results of operations for the six months ended June 30, 2017 are not necessarily indicative of the results to be expected for the year ending December 31, 2017 or for any other interim period or for any other future year.

The accompanying interim unaudited condensed consolidated financial statements and related financial information should be read in conjunction with the audited financial statements and the related notes thereto for the year ended December 31, 2016 included in the Company’s Form 10-K, filed with the SEC on March 31, 2017.

Principles of Consolidation

The accompanying interim unaudited condensed consolidated financial statements are consolidated for the six months ended June 30, 2017 and 2016 and include the accounts of iRhythm Technologies, Inc. and its wholly-owned subsidiary, iRhythm Technologies Ltd., established in March 2016. The financial statements of iRhythm Technologies Ltd. use the U.S. dollar as the functional currency. For all non-functional currency balances, the remeasurement of such balances to functional currency results in a foreign exchange transaction gain or loss, which is recorded in the consolidated statements of operations.

Use of Estimates

The preparation of the condensed consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities as of the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. On an ongoing basis, management evaluates its estimates, including those related to revenue recognition, contractual allowances for revenue, allowance for doubtful accounts, the useful lives of property and equipment, the recoverability of long-lived assets including the estimated usage of the printed circuit board assemblies (“PCBAs”), the valuation of deferred tax assets, the fair value of the Company’s preferred and common stock and stock-based compensation. The Company bases these estimates on historical and anticipated results, trends, and various other assumptions that the Company believes are reasonable under the circumstances, including assumptions as to future events. Actual results may differ from those estimates.

Fair Value of Financial Instruments

The carrying amounts of certain of the Company’s financial instruments, which include cash equivalents, short-term investments, accounts receivable, accounts payable and accrued liabilities, approximate fair value due to their short maturities.

Cash Equivalents

Cash equivalents consist of short-term, highly liquid investments with original maturities of three months or less from the date of purchase.

Investments

Short-term investments consist of debt securities classified as available-for-sale and have maturities greater than 90 days, but less than 365 days from the date of acquisition. Long-term investments have maturities greater than 365 days as of the balance sheet date. All investments are carried at fair value based upon quoted market prices. Unrealized gains and losses on available-for-sale securities are excluded from earnings and are reported as a component of accumulated other comprehensive loss. The cost of available-for-sale securities sold is based on the specific-identification method. Realized gains and losses are included in earnings, and are derived for specific-identification method for determining the costs of investments sold.

Restricted Cash

Restricted cash consists of certificates of deposit held with a financial institution as security deposits for building leases and is included in short-term assets on the Company's condensed consolidated balance sheets.

Accounts Receivable, Allowance for Doubtful Accounts and Contractual Allowance

Accounts receivable consists of amounts due to the Company from institutions, government payors and third-party commercial payors as a result of the Company's normal business activities. Accounts receivable is reported on the condensed consolidated balance sheets net of an estimated allowance for doubtful accounts and contractual allowance.

The Company establishes an allowance for doubtful accounts for estimated uncollectible receivables based on its historical experience, and recognizes the provision as a component of selling, general and administrative expenses. The Company establishes a contractual allowance, which is a reduction in revenue, for estimated uncollectible amounts from Centers for Medicare & Medicaid Services (“CMS”) and contracted third-party commercial payors.

The following table presents the changes in the allowance for doubtful accounts:

	June 30,			December 31,
	2017			2016
Balance, beginning of period	$	1,792		$	1,125
Add: provision for doubtful accounts		1,426			1,960
Less: write-offs, net of recoveries and other adjustments		(378	)		(1,293	)
Balance, end of period	$	2,840		$	1,792

The following table presents the changes in the contractual allowance:

	June 30,			December 31,
	2017			2016
Balance, beginning of period	$	2,340		$	338
Add: contractual allowances		2,790			2,726
Less: write-offs, net of recoveries and other adjustments		(96	)		(724	)
Balance, end of period	$	5,034		$	2,340

Management reviews and updates its estimates for the allowances for doubtful accounts and contractual allowance periodically to reflect its experience regarding historical collections. If management were to make different judgments or utilize different estimates in the allowances for doubtful accounts and contractual allowance, differences in the amount of reported selling, general and administrative expenses and revenue could result, respectively.

Concentrations of Risk

Credit Risk

Financial instruments that potentially subject the Company to a concentration of credit risk consist primarily of cash and cash equivalents, investments and accounts receivable. Cash, cash equivalents, and investments are deposited in financial institutions which, at times, may be in excess of federally insured limits. Cash equivalents are invested in highly rated money market funds. The Company invests in a variety of financial instruments, such as, but not limited to, United States Government securities, corporate notes, commercial paper and, by policy, limits the amount of credit exposure with any one financial institution or commercial issuer. The Company has not experienced any material losses on its deposits of cash and cash equivalents or investments.

Concentrations of credit risk with respect to accounts receivable are limited due to the large number of customers comprising the Company’s customer base and their dispersion across many geographies. The Company does not require collateral. The Company records an allowance for doubtful accounts when it becomes probable that a receivable will not be collected. Government agencies, including CMS and the Veterans Administration, accounted for approximately 38%, 41%, 37% and 41% of the Company’s revenue for the three and six months ended June 30, 2017 and 2016 respectively. Accounts receivable related to government agencies accounted for 16% and 27% at June 30, 2017 and December 31, 2016, respectively.

Supply Risk

While the Company has not experienced manufacturing supply disruptions to date, the Company relies on single-source vendors for the supply of its disposable housings, instruments and other materials used to manufacture the ZIO Patch and the adhesive that binds the ZIO Patch to a patient’s body. These components and materials are critical, and there could be a considerable delay in finding alternative sources of supply.

Inventory

Inventory is stated at the lower of cost or market, cost being determined on a standard cost basis for material costs and on actual cost basis for labor and overhead, which approximates actual cost on a first in, first out (“FIFO)” basis, and market being determined as the lower of cost or net realizable value. The Company records write-downs of inventory that is obsolete or in excess of anticipated demand or market value based on consideration of product lifecycle stage, technology trends, product development plans and assumptions about future demand and market conditions. Actual demand may differ from forecasted demand and such differences may have a material effect on recorded inventory values. Inventory write-downs are charged to cost of revenue and establish a new cost basis for the inventory.

Property and Equipment

Property and equipment are stated at cost less accumulated depreciation and amortization. Depreciation and amortization is computed using the straight-line method over the estimated useful lives of the assets, ranging from three to five years. Leasehold improvements are amortized over the shorter of the lease term or the estimated useful lives of the assets. Maintenance and repairs are charged to expense as incurred and improvements and betterments are capitalized.

Internal-Use Software

The Company capitalizes costs related to internal-use software during the application development stage. Costs related to planning and post implementation activities are expensed as incurred. Capitalized internal-use software is amortized, and recognized as cost of revenue, on a straight-line basis over the estimated useful life, which is up to five years. The Company evaluates the useful lives of these assets on an annual basis and tests for impairment whenever events or changes in circumstances occur that could impact the recoverability of these assets. Capitalized internal-use software costs are classified as a component of property and equipment.

Goodwill

Goodwill represents the excess of the purchase price paid over the fair value of tangible and identifiable intangible net assets acquired in business combinations. Goodwill is tested for impairment on an annual basis and at any other time if events occur or circumstances indicate that the carrying amount of goodwill may not be recoverable. Such events or circumstances may include significant adverse changes in the general business climate, among other things. The impairment test is performed by determining the enterprise fair value of the Company, which is primarily based on the Company’s market capitalization. If the Company’s carrying value, as a one reporting unit entity, is less than its fair value, then the fair value is allocated to all of its assets and liabilities (including any unrecognized intangible assets) as if the fair value was the purchase price to acquire the Company. The excess of the fair value over the amounts assigned to the Company’s assets and liabilities is the implied fair value of the goodwill. If the carrying amount of goodwill exceeds the implied fair value of that goodwill, an impairment loss is recognized in an amount equal to that excess. The Company performs its annual evaluation of goodwill during the fourth quarter of each fiscal year. The Company did not record any charges related to goodwill impairment in any of the periods presented in these condensed consolidated financial statements.

Impairment of Long-Lived Assets

The Company annually reviews long-lived assets for impairment or whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. Recoverability is measured by comparison of the carrying amount to the future net cash flows which the assets are expected to generate. If such assets are considered to be impaired, the impairment to be recognized is measured as the amount by which the carrying amount of the assets exceeds the projected discounted future net cash flows arising from the asset. To date there have been no such impairments of long-lived assets.

Other Assets

Included in the other assets are PCBAs totaling $3.2 million and $2.8 million as of June 30, 2017 and December 31, 2016, respectively. The Company uses a PCBA in each wearable device and it is used numerous times and has a useful life beyond one year. Each time the PCBA is used in a wearable device, a portion of the cost of the PCBA is recorded as a cost of revenue. The Company has based its estimates of how many times a PCBA can be used on testing in research and development, loss rates, product obsolescence, and the amount of time it takes the device to go through the manufacturing, shipping, customer shelf and patient wear time and upload process. The Company periodically evaluates the use estimate.

Comprehensive Loss

Comprehensive loss represents all changes in stockholders' equity except those resulting from and distributions to stockholders. The Company’s unrealized gains and losses on available-for-sale securities represent the only component of other comprehensive loss that are excluded from the reported net loss and that are presented in the condensed consolidated statements of comprehensive loss.

Revenue Recognition

The Company’s devices, cardiac rhythm monitors, have a wear period for up to 14 days for the ZIO Patch Service or 30 days for the ZIO Event Card. The Company's services, consisting of the delivery of reports containing analysis of data captured by the physical device to the prescribing physician, are generally billable at the start of the wear period or when reports are issued to physicians, depending on the service provided. For the ZIO Event Card, the Company recognizes revenue on a straight-line basis over the applicable wear period, as the event monitoring results are delivered to physicians. For the ZIO Patch Service, the Company recognizes the revenue at the time that a report is delivered to a physician. For all services performed, the Company considers whether or not the following revenue recognition criteria are met: persuasive evidence of an arrangement exists and delivery has occurred or services have been rendered. For services performed for customers the Company invoices directly, additional revenue recognition criteria include that the price is fixed and determinable and collectability is reasonably assured; for customers in which the Company submits claims to third-party commercial and governmental payors for reimbursement, it recognizes revenue only when a reasonable estimate of reimbursement can be made.

The assessment of whether a reasonable estimate of reimbursement can be made requires significant judgment by management. Where management's judgment indicates a reasonable estimate of reimbursement can be made, revenue is recognized upon delivery of the patient report for the ZIO Patch Service and straight-line for the ZIO Event Card. Some patients have out-of-pocket costs for amounts not covered by their insurance carrier, and the Company may bill the patient directly for these amounts in the form of co-payments and co-insurance in accordance with their insurance carrier and health plans. Some payors may not cover the Company's service as ordered by the prescribing physician under their reimbursement policies. In the absence of an agreement with the patient or other clearly enforceable legal right to demand payment from the patient, the related revenue is recognized upon the earlier of notification of the payor benefits allowed or when payment is received, until the Company has the ability to make a reasonable estimate. Once a reasonable estimate can be made, revenue is recognized upon delivery of the service. During 2017, the Company recognized revenue from certain non-contracted payors as a reasonable estimate was able to be made, primarily based on the consistency of historical payments.

The Company recognizes revenue related to billings for CMS and commercial payors on an accrual basis, net of contractual allowances, when a reasonable estimate of reimbursement can be made. These contractual allowances represent the difference between the list price (the billing rate) and the reimbursement rate for each payor. Upon ultimate collection from CMS and commercial payors, the amount is compared to the previous estimates and the contractual allowance is adjusted accordingly. Until a contract has been negotiated with a commercial payor, the Company’s services may or may not be covered by these entities' existing reimbursement policies. In addition, patients do not enter into direct agreements with the Company that commit them to pay any portion of the cost of the service in the event that their insurance declines to reimburse the Company. In the absence of an agreement with the patient or other clearly enforceable legal right to demand payment from the patient, the related revenue is recognized upon the earlier of notification of the payor benefits allowed or when payment is received, until the Company has the ability to make a reasonable estimate. Revenue related to non-contracted claims was $2.8 million, $2.4 million, $5.7 million and $4.3 million for the three and six months ended June 30, 2017 and 2016, respectively. Contracted revenue recognized on an accrual basis was $21.1 million, $13.3 million, $39.6 million and $24.3 million for the three and six months ended June 30, 2017 and 2016, respectively.

Certain of the Company’s customers pay the Company directly for the ZIO Service upon shipment of devices. Such advance payments are recorded as deferred revenue on the condensed consolidated balance sheets and revenue is recognized when reports are delivered to physicians.

Cost of Revenue

Cost of revenue is expensed as incurred and includes direct labor, material costs, equipment and infrastructure expenses, amortization of internal-use software, allocated overhead, and shipping and handling. Material costs include both the disposable costs of the device and amortization of the PCBAs. Each time the PCBA is used in a wearable device, a portion of the cost of the PCBA is recorded as a cost of revenue.

Research and Development

The Company’s research and development costs are expensed as incurred. Research and development costs include, but are not limited to, payroll and personnel-related expenses, laboratory supplies, consulting costs and overhead charges.

Income Taxes

The Company uses the asset and liability method to account for income taxes in accordance with the authoritative guidance for income taxes. Under this method, deferred tax assets and liabilities are determined based on future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases, and tax loss and credit carryforwards. Deferred tax assets and liabilities are measured using enacted tax rates applied to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. A valuation allowance is established when necessary to reduce deferred tax assets to the amount expected to be realized.

The Company recognizes the effect of income tax positions only if those positions are more likely than not of being sustained. Recognized income tax positions are measured at the largest amount that is greater than 50% likely of being realized. Changes in recognition or measurement are reflected in the period in which the change in judgment occurs. The Company records interest and penalties related to unrecognized tax benefits in income tax expense. To date, there have been no interest or penalties charged in relation to the unrecognized tax benefits.

Stock-based Compensation

The Company measures its stock-based awards made to employees based on the estimated fair values of the awards as of the grant date. The fair value of stock options are determined using the Black-Scholes option pricing model. Stock-based compensation expense is recognized over the requisite service period using the straight-line method and is based on the value of the portion of stock-based payment awards that is ultimately expected to vest. As such, the Company’s stock-based compensation is reduced for the estimated forfeitures at the date of grant and revised, if necessary, in subsequent periods if actual forfeitures differ from those estimates. For restricted stock, the compensation cost for these awards is based on the closing price of the Company’s common stock on the date of grant, and recognized as compensation expense on a straight-line basis over the requisite service period.

The Company recognizes compensation expense related to the Employee Stock Purchase Program (“ESPP”) based on the estimated fair value of the options on the date of grant, net of estimated forfeitures. The Company estimates the grant date fair value, and the resulting stock-based compensation expense, using the Black-Scholes option pricing model for each purchase period. The grant date fair value is expensed on a straight-line basis over the offering period.

Net Loss per Common Share

Basic net loss per common share is calculated by dividing the net loss by the weighted average number of shares of common stock outstanding during the period, without consideration of potentially dilutive securities. Diluted net loss per common share is the same as basic net loss per common share for all periods presented since the effect of potentially dilutive securities are anti-dilutive.

Recent Accounting Pronouncements

In May 2014, the Financial Accounting Standards Board (“FASB”), issued Accounting Standards Update (“ASU”) No. 2014-09, Revenue from Contracts with Customers (Topic 606). Areas of revenue recognition that will be affected include, but are not limited to, transfer of control, variable consideration, allocation of transfer pricing, licenses, time value of money, contract costs and disclosures. In August 2015, the FASB issued ASU No. 2015-14, Revenue from Contracts with Customers (Topic 606): Deferral of Effective Date, which defers the effective date of ASU 2014-09 by one year allowing early adoption as of the original effective date of fiscal years and interim reporting periods beginning after December 15, 2016, at which time companies may adopt the new standard update under the full retrospective method or the modified retrospective method. The deferral results in the new revenue standard being effective for the Company for fiscal years and interim reporting periods beginning after December 15, 2017. In March, April and May 2016, the FASB issued additional updates to the new revenue standard relating to reporting revenue on a gross versus net basis, identifying performance obligations and licensing arrangements, and narrow-scope improvements and practical expedients, respectively. The Company plans on adopting this standard on January 1, 2018. While in the initial stages of the evaluation of the new standard, the Company believes the adoption will result in timing differences in its recognition of revenue related to non-contracted third-party payors and the recognition of bad debt expense related to patients, which is expected to be included as contra-revenue rather than as a component of selling, general and administrative expenses.

In July 2015, the FASB issued ASU No. 2015-11, Inventory, Simplifying the Measurement of Inventory. Under ASU 2015-11, the measurement principle for inventory will change from lower of cost or market value to lower of cost and net realizable value. Net realizable value is the estimated selling prices in the ordinary course of business, less reasonably predictable costs of completion, disposal and transportation. The ASU is effective for fiscal years and interim periods within those years beginning after December 15, 2016. The Company adopted this guidance effective January 1, 2017, and there was no impact on the condensed consolidated financial statements.

In November 2015, the FASB issued ASU No. 2015-17, Income Taxes (Topic 740): Balance Sheet Classification of Deferred Taxes. Under ASU 2015-17, deferred tax liabilities and assets will be classified as noncurrent on the balance sheet. Previous guidance required deferred tax liabilities and assets to be separated into current and noncurrent amounts on the balance sheet. The guidance is effective for annual periods beginning after December 15, 2016 and for interim periods within those annual periods. Early adoption is permitted. The Company adopted this guidance effective January 1, 2017, and there was no impact on the condensed consolidated financial statements.

In January 2016, the FASB issued ASU No. 2016-01, Recognition and Measurement of Financial Assets and Financial Liabilities, which addresses certain aspects of recognition, measurement, presentation and disclosure of financial instruments. ASU 2016-01 is effective for annual periods, and interim periods within those annual periods, beginning after December 15, 2017. The Company has not determined the potential effects of this ASU on its consolidated financial statements.

In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842), which requires a lessee to recognize assets and liabilities on its consolidated balance sheet for leases with accounting lease terms of more than 12 months. ASU 2016-02 will replace most existing lease accounting guidance in U.S. GAAP when it becomes effective. The new standard states that a lessee will recognize a lease liability for the obligation to make lease payments and a right-of-use asset for the right to use the underlying asset for the lease term. Leases will be classified as either finance or operating, with classification affecting the pattern of expense recognition in the consolidated statements of operations. ASU 2016-02 will be effective for our first quarter of fiscal 2020 and requires the modified retrospective method of adoption. Early adoption is permitted. Although the Company is currently evaluating the effect that ASU 2016-02 will have on its consolidated financial statements and related disclosures, the Company expects that most of its operating lease commitments will be subject to the new standard and recognized as operating lease liabilities and right-of-use assets upon adoption.

In March 2016, the FASB issued ASU No. 2016-09, Compensation—Stock Compensation (Topic 718). This ASU was issued as part of the FASB’s simplification initiative and affects all entities that issue share-based payment awards to their employees. This standard covers accounting for income taxes, forfeitures, and statutory tax withholding requirements, as well as classification in the statement of cash flows. As a result of adopting ASU No. 2016‑09 on January 1, 2017, the Company has made an accounting policy election to continue to estimate forfeitures. The adoption of ASU No. 2016‑09 also requires excess tax benefits and tax deficiencies be recorded in the income statement as opposed to additional paid‑in capital when the awards vest or are settled, and has been applied on a prospective basis with no impact on the condensed consolidated financial statements as of and for the three months ended June 30, 2017. As a result of the adoption, the Company increased its total NOLs by $0.1 million on January 1, 2017 related to deferred tax assets that arose directly from tax deductions related to equity compensation greater than compensation recognized for financial reporting purposes. This amount is fully offset by the valuation allowance.

In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments – Credit Losses (Topic 326), which is intended to provide financial statement users with more useful information about expected credit losses on financial assets held by a reporting entity at each reporting date. The new standard replaces the existing incurred loss impairment methodology with a methodology that requires consideration of a broader range of reasonable and supportable forward-looking information to estimate all expected credit losses. This ASU is effective for fiscal years and interim periods within those years beginning after December 15, 2019 and early adoption is permitted for fiscal years and interim periods within those years beginning after December 15, 2018. The Company is currently evaluating the impact of this new guidance.

In August 2016, the FASB issued ASU No. 2016-15, Statement of Cash Flows (Topic 230) – Classification of Certain Cash Receipts and Cash Payments, which clarifies the classification of certain cash receipts and cash payments in the statements of cash flow to eliminate the diversity in practice related to eight specific cash flow issues. This ASU is effective for fiscal years and interim periods within those years beginning after December 15, 2017, with early adoption permitted. The Company is currently evaluating the impact of this new guidance.

In November 2016, the FASB issued ASU No. 2016-18, Statement of Cash Flows (Topic 230) – Restricted Cash, which requires the presentation of changes in restricted cash or restricted cash equivalents on the statement of cash flows. This ASU is effective for the fiscal years and interim periods within those years beginning after December 15, 2017, with early adoption permitted. The Company is currently evaluating the impact of this new guidance.

In January 2017, the FASB issued ASU No. 2017-04, Intangibles—Goodwill and Other (Topic 350) – Simplifying the Test for Goodwill Impairment, which simplifies the measurement of goodwill by eliminating the Step 2 impairment test. Step 2 measures a goodwill impairment loss by comparing the implied fair value of a reporting unit’s goodwill with the carrying amount of that goodwill. The new guidance required an entity to compare the fair value of a reporting unit with its carrying amount and recognize an impairment charge for the amount by which the carrying amount exceeds the reporting unit’s fair value. Additionally, an entity should consider income tax effects from any tax deductible goodwill on the carrying amount of the reporting unit when measuring the goodwill impairment loss, if applicable. The new guidance becomes effective for goodwill impairment tests in fiscal years beginning after December 15, 2019, though early adoption is permitted. The Company is currently assessing the impact of this new guidance.

On May 10, 2017, the FASB issued ASU 2017-09, Scope of Modification Accounting, which amends the scope of modification accounting for share-based payment arrangements, provides guidance on the types of changes to the terms or conditions of share-based payment awards to which an entity would be required to apply modification accounting under ASC 718. This ASU is effective for annual reporting periods, including interim periods within those annual reporting periods, beginning after December 15, 2017, with early adoption permitted. The Company is currently evaluating the impact of this new guidance.

Cash Equivalents and Investments

6 Months Ended

Jun. 30, 2017

Cash And Cash Equivalents [Abstract]

Cash Equivalents and Investments

3. Cash Equivalents and Investments

The fair value of securities, not including cash at June 30, 2017 and December 31, 2016, were as follows (in thousands):

	June 30, 2017
	Amortized		Gross Unrealized					Estimated
	Cost		Gains		Losses			Fair Value
Money market funds	$	13,059	$	—	$	—		$	13,059
U.S. government securities		32,937		—		(45	)		32,892
Corporate notes		24,263		1		(6	)		24,258
Commercial paper		36,428		—		—			36,428
Total available-for-sale securities	$	106,687	$	1	$	(51	)	$	106,637
Classified as:
Cash equivalents								$	13,059
Short-term investments									93,578
Long-term investments									—
Total cash equivalents and investments								$	106,637

	December 31, 2016
	Amortized		Gross Unrealized					Estimated
	Cost		Gains		Losses			Fair Value
Money market funds	$	45,937	$	—	$	—		$	45,937
U.S. government securities		16,479		11		—			16,490
Corporate notes		23,947		—		(20	)		23,927
Commercial paper		24,971		—		—			24,971
Total available-for-sale securities	$	111,334	$	11	$	(20	)	$	111,325
Classified as:
Cash equivalents								$	45,937
Short-term investments									54,407
Long-term investments									10,981
Total cash equivalents and investments								$	111,325

Available-for-sale securities held as of June 30, 2017 had a weighted average days to maturity of 126 days. There have been no material realized gains or realized losses on available-for-sale securities for the periods presented.

As the carrying value approximates the fair value for the Company’s cash equivalents, short-term and long-term investments shown in the tables above, the following table summarizes the fair value of the Company’s cash equivalents, short-term and long-term investments classified by maturity (in thousands):

	June 30,		December 31,
	2017		2016
Due within one year	$	106,637	$	100,344
Due after one year through three years		—		10,981
Total available-for-sale marketable debt securities	$	106,637	$	111,325

Fair Value Measurements

6 Months Ended

Jun. 30, 2017

Fair Value Disclosures [Abstract]

Fair Value Measurements

4. Fair Value Measurements

The Company discloses and recognizes the fair value of its assets and liabilities using a hierarchy that prioritizes the inputs to valuation techniques used to measure fair value. Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability (an exit price) in an orderly transaction between market participants at the reporting date. The hierarchy gives the highest priority to valuations based upon unadjusted quoted prices in active markets for identical assets or liabilities (Level 1 measurements) and the lowest priority to valuations based upon unobservable inputs that are significant to the valuation (Level 3 measurements). The guidance establishes three levels of the fair value hierarchy as follows:

Level 1 - Inputs are unadjusted quoted prices in active markets for identical assets or liabilities at the measurement date.

Level 2 - Inputs (other than quoted market prices included in Level 1) are either directly or indirectly observable for the asset or liability through correlation with market data at the measurement date and for the duration of the instrument’s anticipated life.

Level 3 - Inputs reflect management’s best estimate of what market participants would use in pricing the asset or liability at the measurement date. Consideration is given to the risk inherent in the valuation technique and the risk inherent in the inputs to the model.

Assets and liabilities measured at fair value are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. The Company’s assessment of the significance of a particular input to the fair value measurement in its entirety requires management to make judgments and consider factors specific to the asset or liability. The corporate notes, commercial paper and government bonds are classified as Level 2 as they were valued based upon quoted market prices for similar instruments in active markets, quoted prices for identical or similar instruments in markets that are not active and model-based valuation techniques for which all significant inputs are observable in the market or can be corroborated by observable market data for substantially the full term of the assets.

Based on Level 2 inputs and the borrowing rates currently available to the Company for loans with similar terms and maturities, the carrying value of the Company’s debt approximates its fair value.

The following table presents the fair value of the Company’s financial assets and liabilities determined using the inputs defined above (amounts in thousands).

	June 30, 2017
	Level 1		Level 2		Level 3		Total
Assets
Money market funds	$	13,059	$	—	$	—	$	13,059
U.S. government securities		—		32,892		—		32,892
Corporate notes		—		24,258		—		24,258
Commercial paper		—		36,428		—		36,428
Total	$	13,059	$	93,578	$	—	$	106,637

	December 31, 2016
	Level 1		Level 2		Level 3		Total
Assets
Money market funds	$	45,937	$	—	$	—	$	45,937
U.S. government securities		—		16,490		—		16,490
Corporate notes		—		23,927		—		23,927
Commercial paper		—		24,971		—		24,971
Total	$	45,937	$	65,388	$	—	$	111,325

The following table sets forth a summary of the changes in the fair value of the preferred stock warrants which is classified as Level 3 in the fair value hierarchy. There were no transfers into or out of Level 3 during the periods (in thousands):

	Six Months Ended June 30, 2017		Six Months Ended June 30, 2016
Beginning balance	$	—	$	2,949
Total change in fair value recorded as other expense, net		—		397
Ending balance	$	—	$	3,346

The valuation of the preferred stock warrant liabilities is discussed in Note 11.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Balance Sheet Components

6 Months Ended

Jun. 30, 2017

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Balance Sheet Components

5. Balance Sheet Components

Inventory and PCBAs

Inventory and PCBAs consisted of the following (in thousands):

	June 30, 2017		December 31, 2016
Raw materials	$	1,051	$	839
Finished goods		3,411		3,324
Total	$	4,462	$	4,163

Reported on the consolidated balance sheet as:
Inventory	$	1,231	$	1,390
Other assets		3,231		2,773
Total	$	4,462	$	4,163

Amounts reported as other assets are comprised of the PCBA costs that are included in both raw materials and finished goods totals above.

Property and Equipment, Net

Property and equipment, net consisted of the following (in thousands):

	June 30,			December 31,
	2017			2016
Laboratory and manufacturing equipment	$	1,896		$	1,509
Computer equipment and software		842			736
Furniture and fixtures		679			657
Leasehold improvements		733			502
Internal-use software		4,302			2,900
Total property and equipment, gross		8,452			6,304
Less: accumulated depreciation and amortization		(2,286	)		(1,651	)
Total property and equipment, net	$	6,166		$	4,653

Depreciation and amortization expense for the three and six months ended June 30, 2017 and 2016 was $0.3 million, $0.2 million, $0.6 million and $0.4 million, respectively.

Accrued Liabilities

Accrued liabilities consisted of the following (in thousands):

	June 30,		December 31,
	2017		2016
Accrued vacation	$	1,988	$	1,642
Accrued payroll and related expenses		4,970		6,179
Accrued ESPP contributions		232		417
Accrued professional services fees		1,152		636
Other		1,643		1,291
Total accrued liabilities	$	9,985	$	10,165

Related-Party Transactions	6 Months Ended
Related-Party Transactions	Jun. 30, 2017
Related Party Transactions [Abstract]
Related-Party Transactions	6. Related-Party Transactions Kaiser Permanente (“Kaiser”) is a common stockholder of the Company, representing 6.1% ownership of the total outstanding shares of the Company as of December 31, 2016. For the three and six months ended June 30, 2017 and 2016, the Company recognized revenue of $1.0 million, $0.6 million, $1.8 million and $1.4 million, respectively, for transactions with Kaiser. The amounts receivable from transactions with Kaiser were $0.5 million, and $0.4 million as of June 30, 2017 and December 31, 2016, respectively. Kaiser performs services related to clinical trials and the Company utilizes Kaiser for employee healthcare and the total expense recorded was $0.3 million, $0.2 million, $0.3 million, and $0.3 million as of the three and six months ended June 30, 2017 and 2016, respectively. The amounts outstanding and included in accounts payable and accrued liabilities were $0.1 million and $0.2 million as of June 30, 2017, and December 31, 2016 respectively.

Commitments and Contingencies

6 Months Ended

Jun. 30, 2017

Commitments And Contingencies Disclosure [Abstract]

Commitments and Contingencies

7. Commitments and Contingencies

Lease Arrangements

The Company leases office and manufacturing space under non-cancelable operating leases which expire on various dates through 2027. These leases generally contain scheduled rent increases or escalation clauses and renewal options. The Company recognizes rent expense on a straight-line basis over the lease period.

In May 2017, the Company entered into a commercial building lease agreement for its clinical center in Houston, Texas which expires in September 2027.

The following table summarizes the Company’s future minimum lease payments as of June 30, 2017 (in thousands):

Period Ending December 31:
2017 (remainder of year)	$	2,491
2018		5,089
2019		5,108
2020		1,178
2021		406
Thereafter		2,541
Total	$	16,813

The Company’s rent expense was $1.4 million, $0.5 million, $2.5 million and $0.9 million for the three and six months ended June 30, 2017 and 2016, respectively.

Legal Proceedings

From time to time, the Company may become involved in legal proceedings arising from the ordinary course of its business. Management is currently not aware of any matters that could have a material adverse effect on the financial position, results of operations or cash flows of the Company.

Indemnifications

In the ordinary course of business, the Company enters into agreements that may include indemnification provisions. Pursuant to such agreements, the Company may indemnify, hold harmless and defend an indemnified party for losses suffered or incurred by the indemnified party. Some of the provisions will limit losses to those arising from third-party actions. In some cases, the indemnification will continue after the termination of the agreement. The maximum potential amount of future payments the Company could be required to make under these provisions is not determinable. The Company has also entered into indemnification agreements with its directors and officers that may require the Company to indemnify its directors and officers against liabilities that may arise by reason of their status or service as directors or officers to the fullest extent permitted by California corporate law. The Company currently has directors’ and officers’ insurance. The Company has never incurred material costs to defend lawsuits or settle claims related to these indemnification provisions, and believes that the estimated fair value of these indemnification obligations is not material and it has not accrued any amounts for these obligations.

Debt	6 Months Ended
Debt	Jun. 30, 2017
Debt Disclosure [Abstract]
Debt	8. Debt Pharmakon Loan Agreement In December 2015, the Company entered into the Loan Agreement with Biopharma Secured Investments III Holdings Cayman LP, or Pharmakon (the “Pharmakon Loan Agreement”). The Pharmakon Loan Agreement provides for up to $55.0 million in term loans split into two tranches as follows: (i) the Tranche A Loans are $30.0 million in term loans, and (ii) the Tranche B Loans are up to $25.0 million in term loans. The Tranche A Loans were drawn on December 4, 2015. The Tranche B Loans were available to be drawn prior to December 4, 2016. No additional draw was made. During the first full eight quarters, payments are interest only and for the first two years, 50% of the interest will be “paid-in-kind.” The Company is subject to a financial covenant related to minimum trailing revenue targets that begins in June 2017, and is tested on a semi-annual basis. The minimum net revenue covenant ranges from $44.7 million for the period ended June 30, 2017 to $102.6 million for the period ended December 31, 2021, which was achieved as of June 30, 2017. The minimum net revenues financial covenant has a 45-day equity cure period following required delivery date of the financial statements. Pursuant to this equity cure provision, the Company may cure a revenue covenant default by raising additional funds from the sale of equity. The loan matures December 2021. The Tranche A Loans bear interest at a fixed rate equal to 9.50% per annum that is due and payable quarterly in arrears. During the first eight calendar quarters, 50% of the interest due and payable shall be added to the then outstanding principal. The Pharmakon Loan Agreement requires the Company to maintain a minimum consolidated liquidity and minimum net revenue during the term of the loan facility and contains customary affirmative and negative covenants and event of default provisions that could result in the acceleration of the repayment obligations under the loan facility. Upon a change in control of the Company, Pharmakon has the option to demand payment in full of the outstanding loans together with any prepayment premium. The obligations under the Pharmakon Loan Agreement are secured by a security interest in substantially all of the Company’s assets pursuant to the Pharmakon Guaranty and Security Agreement and this security interest is governed by an intercreditor agreement between Pharmakon and Silicon Valley Bank (“SVB”). In December 2015, the Company used the proceeds from the Pharmakon Loan Agreement to repay $4.9 million of bank debt to SVB. The issuance costs and debt discount have been netted against the borrowed funds on the balance sheet. The debt balance as of June 30, 2017 and December 31, 2016 was $31.6 million and $30.8 million, respectively. Bank Debt In June 2014, the Company refinanced its debt with SVB by entering into the Second Amendment to the Amended and Restated Loan Security Agreement (“Second Amendment”). Under this amendment, the Company borrowed $4.9 million with an additional advance of $5.0 million available. All the borrowings under the Second Amended Loan Agreement were collateralized by all of the Company’s assets, excluding intellectual property. In connection with entering into the Amended Loan Agreement, the Company issued warrants to purchase 20,136 shares of Series D at $7.31 per share that expire in June 2024 (See Note 11). In December 2015, the Company used the proceeds from the Pharmakon Loan Agreement to repay $4.9 million of bank debt to SVB and entered into a Second Amended and Restated Loan and Security Agreement with SVB, or the SVB Loan Agreement. Under the SVB Loan Agreement the Company may borrow, repay and reborrow under a revolving credit line, but not in excess of the maximum loan amount of $15.0 million, until December 4, 2018, when all outstanding principal and accrued interest becomes due and payable. Any principal amount outstanding under the SVB revolving credit line shall bear interest at a floating rate per annum equal to the rate published by The Wall Street Journal as the “Prime Rate” plus 0.25%, are tied to the Company’s trailing six-month revenue and subject to certain revenue targets. The Company may borrow up to 80% of its eligible accounts receivable, up to the maximum of $15.0 million. In August 2016, the Company obtained a $3.1 million standby letter of credit pursuant to the SVB revolving credit facility in connection with a lease for the San Francisco office. As of June 30, 2017 and December 31, 2016, the Company was eligible to borrow up to $8.1 million and $2.5 million, respectively, under the SVB revolving credit line. The SVB Loan Agreement requires the Company to maintain a minimum consolidated liquidity and minimum net sales during the term of the loan facility. In addition, the SVB Loan Agreement contains customary affirmative and negative covenants and events of default. The obligations under the SVB Loan Agreement are collaterialized by substantially all assets of the Company and this security interest is governed by an intercreditor agreement between Pharmakon and SVB. California HealthCare Foundation Note In November 2012, the Company entered into a Note Purchase Agreement and Promissory Note with the California HealthCare Foundation, or the CHCF Note, through which the Company borrowed $1.5 million. The CHCF Note accrues simple interest of 2.0%. The accrued interest and the principal was to mature in November 2016. In partial consideration for the issuance of the CHCF Note, the Company issued warrants to purchase 22,807 shares of the Company’s Series D convertible preferred stock. In June 2015, the Company amended the CHCF Note to extend the maturity date to May 2018. In partial consideration for the amendment, the Company issued 8,552 warrants at $6.58 exercise price per share of the Company’s Series D convertible preferred stock. The CHCF note is subordinate to other debt. The debt balance, net of debt discount, as of June 30, 2017 and December 31, 2016 was $1.5 million and $1.5 million, respectively.

Income Taxes	6 Months Ended
Income Taxes	Jun. 30, 2017
Income Tax Disclosure [Abstract]
Income Taxes	9. Income Taxes The Company did not record a provision or benefit for income taxes during the six months ended June 30, 2017 and 2016, respectively, as it reported losses in each period which are not more likely than not to be realized. Due to the uncertainties surrounding the realization of deferred tax assets through future taxable income, the Company has provided a full valuation allowance and, therefore, no benefit has been recognized for the net operating loss carryforwards and other deferred tax assets. At December 31, 2016, the Company had $0.6 million of unrecognized tax benefit, none of which, if recognized, would affect the effective tax rate as most of the unrecognized tax benefit is deferred tax assets currently offset by a valuation allowance. A number of years may elapse before an uncertain tax position is audited and finally resolved. While it is often difficult to predict the final outcome or the timing of resolution of any particular uncertain tax position, the Company believes that its reserves for income taxes reflect the most likely outcome. The Company adjusts these reserves in light of changing facts and circumstances. Settlement of any particular position could require the use of cash. As of June 30, 2017, changes to the Company’s uncertain tax positions in the next twelve months that are reasonably probable are not expected to have a material impact on the Company’s financial position or results of operations.

Stockholders' Equity

6 Months Ended

Jun. 30, 2017

Equity [Abstract]

Stockholders' Equity

10. Stockholders’ Equity

Common stock

As of June 30, 2017, the Company’s amended and restated certificate of incorporation dated October 2016, authorized the Company to issue 100,000,000 shares of common stock with a par value of $0.001 per share and 5,000,000 shares of preferred stock with a par value of $0.001 per share. The holders of common stock are entitled to receive dividends whenever funds and assets are legally available and when declared by the board of directors. No dividends were declared through June 30, 2017.

The Company had reserved shares of common stock for issuance as follows:

	June 30,		December 31,
	2017		2016
Options issued and outstanding		3,107,386		2,977,218
Unvested restricted stock units		366,684		105,529
Common stock warrants issued and outstanding		143,795		217,245
Shares available for grant under future stock plans		4,893,448		4,226,068
		8,511,313		7,526,060

Preferred Stock Warrant Liabilities	6 Months Ended
Preferred Stock Warrant Liabilities	Jun. 30, 2017
Preferred Stock Warrant Liabilities [Abstract]
Preferred Stock Warrant Liabilities	11. Preferred Stock Warrant Liabilities In November 2012, in connection with borrowings under a convertible note, the Company issued warrants to purchase shares of Series C or New Preferred. The warrants were only exercisable if the Convertible Notes were converted into Series C or New Preferred. The warrants’ exercise price is $0.001 per share and they have a seven year term. On March 27, 2013 the Company closed the Series D financing. The warrants were converted into warrants to purchase 207,177 shares of Series D convertible preferred stock. The Company recognized a charge of $59,000 and income of $235,000 related to the change in the fair value of the warrants for the three and six months ended June 30, 2016. Upon the IPO, the Series D preferred stock warrants converted into common stock warrants and were reclassified to additional paid-in-capital in the Company's balance sheet. As a result, the warrants are no longer subject to fair value remeasurement. As of June 30, 2017, 143,795 warrants were outstanding. In June 2014, in connection with borrowings under the Second Amendment (Note 8), the Company issued warrants to purchase 20,136 shares of Series D Preferred Stock at $7.31 per share that expire June 2024. The fair value of the warrants was determined by using an option pricing model prepared by a third-party based on an allocation of the Company’s aggregate value to the outstanding equity instruments, applying a 30% discount to the warrant value for lack of marketability. The fair value of the warrant, $98,000, was recorded as a debt discount and is being amortized over the loan repayment period to interest expense. The Company recognized a charge of $1,000 and income of $26,000 related to change in the fair value of the warrants for the three and six months ended June 30, 2016. The warrants were converted into warrants to purchase common stock upon the completion of the IPO in 2016, and were reclassified to additional paid-in-capital in the Company's balance sheet. One of the warrants for 10,068 shares was exercised through a cashless exercise on October 26, 2016 resulting in the issuance of a net 7,310 shares of the Company's common stock, and the other warrant for 10,068 was exercised through a cashless exercise on May 2, 2017 resulting in the issuance of a net 8,077 shares.

Stock Incentive Plans

6 Months Ended

Jun. 30, 2017

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Stock Incentive Plans

12. Stock Incentive Plans

2006 Plan

In October 2006, the Company adopted the 2006 Equity Incentive Plan, as amended, (the “2006 Plan”). The Plan provided for the granting of stock options to employees and non-employees of the Company. Options granted under the Plan were either incentive stock options or nonqualified stock options. Incentive stock options (“ISO”) were granted only to employees (including officers and directors who are also employees). Nonqualified stock options (“NSO”) were granted to employees and non-employees. The board of directors had the authority to determine to whom options will be granted, the number of options, the term and the exercise price.

Options under the Plan were granted for periods of up to ten years and at the fair value of the shares on the date of grant as determined by the board of directors. In general, options were exercisable at a rate of 25% after the first anniversary of the grant and then monthly vesting for an additional three years from date of grant. The term for options is no longer than five years for ISOs for which the grantee owns greater than 10% of the voting power of all classes of stock and no longer than ten years for all other options. The Company issues new shares upon the exercise of options.

2016 Plan

In October 2016, the Company adopted the 2016 Equity Incentive Plan, (the “2016 Plan”). The 2016 Plan was subsequently approved by the Company’s stockholders and became effective on October 19, 2016, immediately before the effective date of the IPO. Following the effectiveness of the 2016 Plan, no additional options were granted under the 2006 Plan. In addition, to the extent that any awards outstanding or subject to vesting restrictions under the 2006 Plan are subsequently forfeited or terminated for any reason before being exercised or settled, the shares of common stock reserved for issuance pursuant to such awards as of the closing of the IPO will become available for issuance under the 2016 Plan. The remaining shares available for grant under the 2006 Plan became available for issuance under the 2016 Plan upon the closing of the IPO. On the first day of each year beginning with 2017, the 2016 Plan authorizes an annual increase of the least of 3,865,000 shares, 5% of outstanding common stock on the last day of the immediately preceding fiscal year or an amount as determined by the Company's Board of Directors. As of June 30, 2017, the Company has reserved 4,971,966 shares of common stock for issuance under the 2016 Stock Incentive Plan.

Pursuant to the 2016 Plan, stock options, restricted shares, stock units, including restricted stock units and stock appreciation rights, may be granted to employees, consultants, and outside directors of the Company. Options granted may be either ISOs or NSOs.

Stock options are governed by stock option agreements between the Company and recipients of stock options. ISOs and NSOs may be granted under the 2016 Plan at an exercise price of not less than 100% of the fair market value of the common stock on the date of grant, determined by the Compensation Committee of the Board of Directors. Options become exercisable and expire as determined by the Compensation Committee, provided that the term of ISOs may not exceed ten years from the date of grant.

Employee Stock Purchase Program (“ESPP”)

In October 2016, the Company’s Board of Directors and stockholders approved the Employee Stock Purchase Plan (the “ESPP”). Under the ESPP, the Company initially reserved 483,031 shares of common stock for issuance as of its effective date of October 19, 2016. On the first day of each calendar year, beginning in 2017, the number of shares in the reserve will increase by the lesser of 966,062 shares, 1.5% of the shares of the Company’s common stock outstanding on the last day of the immediately preceding fiscal year, or an amount as determined by the Company’s Board of Directors. The ESPP allows eligible employees to purchase shares of the Company’s common stock at a discount through payroll deductions of up to 15% of their eligible compensation, subject to any plan limitations. The ESPP provides for twelve-month offering periods that each contain two six-month purchase periods. At the end of each purchase period, employees are able to purchase shares at 85% of the lower of the fair market value of the Company’s common stock on the first trading day of the offering period or on the last day of the purchase period.

As of June 30, 2017, 105,128 shares of common stock have been issued to employees participating in the ESPP and 709,993 shares were available for issuance under the ESPP.

Equity Incentive Plan Activity

A summary of share-based awards available for grant under the 2016 Plan is as follows:

	Options Available for Grant
Balance at December 31, 2015		331,938
Additional options authorized		3,865,000
Options granted		(466,914	)
Options forfeited		13,013
Balance at December 31, 2016		3,743,037
Additional options authorized		1,106,966
Options granted		(675,071	)
Options forfeited		8,523
Balance at June 30, 2017		4,183,455

The following table summarizes stock option activity under the 2006 and 2016 Plans, including grants to non-employees:

				Options Outstanding
	Options Outstanding			Weighted- Average Exercise Price Per Share		Weighted- Average Remaining Contractual Life (years)		Aggregate Intrinsic Value (in thousands)
Balances at December 31, 2015		2,685,913		$	4.81		7.63	$	11,589
Options granted		361,385			15.65
Options exercised		(57,067	)		2.33
Options forfeited		(13,013	)		6.92
Balances at December 31, 2016		2,977,218			6.16		6.93	$	70,979
Options granted		411,183			35.59
Options exercised		(272,492	)		3.08
Options forfeited		(8,523	)		18.53
Balances at June 30, 2017		3,107,386		$	10.29		7.29	$	100,068
Options exercisable – June 30, 2017		1,886,915		$	4.79		6.28	$	71,128
Options vested and expected to vest – June 30, 2017		3,028,901		$	9.97		7.24	$	98,486

The aggregate intrinsic values of options outstanding, exercisable, vested and expected to vest were calculated as the difference between the exercise price of the options and the closing price of the Company’s common stock.

During the six months ended June 30, 2017 and 2016, the estimated weighted-average grant-date fair value of common stock underlying options granted was $18.33 and $5.75 per share, respectively.

Stock-Based Compensation

6 Months Ended

Jun. 30, 2017

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Stock-Based Compensation

13. Stock-Based Compensation

Employee Stock Options Valuation

The fair value of employee and director stock options was estimated at the date of grant using a Black-Scholes option valuation model with the weighted average assumptions below.

	Three Months Ended June 30						Six Months Ended June 30
	2017			2016			2017			2016
Expected term (in years)		6.1			6.1			6.1			6.1
Expected volatility		48.1	%		60.0	%		52.6	%		60.0	%
Risk-free interest rate		2.00	%		1.52	%		2.08	%		1.48	%
Dividend yield		0.0	%		0.0	%		0.0	%		0.0	%

Stock-Based Compensation

The following table summarizes the total stock-based compensation expense included in the statements of operations and comprehensive loss for all periods presented (in thousands):

	Three Months Ended June 30				Six Months Ended June 30
	2017		2016		2017		2016
Cost of revenue	$	38	$	3	$	76	$	5
Research and development		383		33		752		69
Selling, general and administrative		1,844		407		3,464		776
Total stock-based compensation expense	$	2,265	$	443	$	4,292	$	850

As June 30, 2017, there was total unamortized compensation costs of $10.1 million, net of estimated forfeitures, related to unvested stock options which the Company expects to recognize over a period of approximately 2.7 years, $9.4 million, net of estimated forfeitures, related to unrecognized restricted stock unit (“RSU”) expense, which the Company expects to recognize over a period of 3.0 years, and $0.9 million unrecognized ESPP expense, which the company will recognize over 0.9 years.

Non-Employee Stock-Based Compensation

Stock-based compensation expense related to stock options granted to non-employees is recognized as the stock options are earned. The measurement of stock-based compensation for non-employees is subject to periodic adjustment as the underlying equity instruments vest, and the related compensation expense is based on the estimated fair value of the equity instruments using the Black-Scholes option pricing model. The Company believes that the estimated fair value of the stock options is more readily measurable than the fair value of the services received. Such expense was not material for the three and six months ended June 30, 2017 and 2016.

Net Loss Per Common Share

6 Months Ended

Jun. 30, 2017

Earnings Per Share [Abstract]

Net Loss Per Common Share

14. Net Loss Per Common Share

As the Company had net losses for the three and six months ended June 30, 2017 and 2016, all potential common shares were determined to be anti-dilutive. The following table sets forth the computation of the basic and diluted net loss per share attributable to common stockholders (in thousands, except share and per share data):

	Three Months Ended June 30,						Six Months Ended June 30,
	2017			2016			2017			2016
Numerator:
Net loss	$	(6,444	)	$	(4,436	)	$	(11,747	)	$	(10,562	)
Denominator:
Weighted-average shares used to compute net loss per common share, basic and diluted		22,362,608			1,435,483			22,257,849			1,424,278
Net loss per common share, basic and diluted	$	(0.29	)	$	(3.09	)	$	(0.53	)	$	(7.42	)

The following outstanding shares of potentially dilutive securities have been excluded from diluted net loss per common share for the three and six months ended June 30, 2017 and 2016, because their inclusion would be anti-dilutive:

	As of June 30,
	2017		2016
Convertible preferred stock on an as-if converted basis		—		13,343,981
Options to purchase common stock		3,107,386		2,722,648
RSUs issued and unvested		366,684		—
Warrants to purchase convertible preferred stock on an as-if converted basis		—		328,114
Warrants to purchase common stock		143,795		—
Total		3,617,865		16,394,743

Summary of Significant Accounting Policies (Policies)

6 Months Ended

Jun. 30, 2017

Accounting Policies [Abstract]

Basis of Presentation

Principals of Consolidation

Principles of Consolidation

Use of Estimates

Fair Value of Financial Instruments

Cash Equivalents

Cash equivalents consist of short-term, highly liquid investments with original maturities of three months or less from the date of purchase.

Investments

Restricted Cash

Accounts Receivable, Allowance for Doubtful Accounts and Contractual Allowance

The following table presents the changes in the allowance for doubtful accounts:

	June 30,			December 31,
	2017			2016
Balance, beginning of period	$	1,792		$	1,125
Add: provision for doubtful accounts		1,426			1,960
Less: write-offs, net of recoveries and other adjustments		(378	)		(1,293	)
Balance, end of period	$	2,840		$	1,792

The following table presents the changes in the contractual allowance:

	June 30,			December 31,
	2017			2016
Balance, beginning of period	$	2,340		$	338
Add: contractual allowances		2,790			2,726
Less: write-offs, net of recoveries and other adjustments		(96	)		(724	)
Balance, end of period	$	5,034		$	2,340

Concentration of Credit Risk

Concentrations of Risk

Credit Risk

Concentration of Supply Risk

Supply Risk

Inventory

Property and Equipment

Internal-Use Software

Goodwill

Impairment of Long-Lived Assets

Research and Development

Income Taxes

Stock-based Compensation

Net Loss per Common Share

Recent Accounting Pronouncements

Summary of Significant Accounting Policies (Tables)

6 Months Ended

Jun. 30, 2017

Accounting Policies [Abstract]

Schedule of Changes in Allowance for Doubtful Accounts

The following table presents the changes in the allowance for doubtful accounts:

	June 30,			December 31,
	2017			2016
Balance, beginning of period	$	1,792		$	1,125
Add: provision for doubtful accounts		1,426			1,960
Less: write-offs, net of recoveries and other adjustments		(378	)		(1,293	)
Balance, end of period	$	2,840		$	1,792

Schedule of Changes in Contractual Allowance

The following table presents the changes in the contractual allowance:

	June 30,			December 31,
	2017			2016
Balance, beginning of period	$	2,340		$	338
Add: contractual allowances		2,790			2,726
Less: write-offs, net of recoveries and other adjustments		(96	)		(724	)
Balance, end of period	$	5,034		$	2,340

Cash Equivalents and Investments (Tables)

6 Months Ended

Jun. 30, 2017

Cash And Cash Equivalents [Abstract]

Schedule of Fair Value of Securities, not Including Cash

The fair value of securities, not including cash at June 30, 2017 and December 31, 2016, were as follows (in thousands):

	June 30, 2017
	Amortized		Gross Unrealized					Estimated
	Cost		Gains		Losses			Fair Value
Money market funds	$	13,059	$	—	$	—		$	13,059
U.S. government securities		32,937		—		(45	)		32,892
Corporate notes		24,263		1		(6	)		24,258
Commercial paper		36,428		—		—			36,428
Total available-for-sale securities	$	106,687	$	1	$	(51	)	$	106,637
Classified as:
Cash equivalents								$	13,059
Short-term investments									93,578
Long-term investments									—
Total cash equivalents and investments								$	106,637

	December 31, 2016
	Amortized		Gross Unrealized					Estimated
	Cost		Gains		Losses			Fair Value
Money market funds	$	45,937	$	—	$	—		$	45,937
U.S. government securities		16,479		11		—			16,490
Corporate notes		23,947		—		(20	)		23,927
Commercial paper		24,971		—		—			24,971
Total available-for-sale securities	$	111,334	$	11	$	(20	)	$	111,325
Classified as:
Cash equivalents								$	45,937
Short-term investments									54,407
Long-term investments									10,981
Total cash equivalents and investments								$	111,325

Schedule of Fair Value of Short-term and Long-term Marketable Securities Classified by Maturity

	June 30,		December 31,
	2017		2016
Due within one year	$	106,637	$	100,344
Due after one year through three years		—		10,981
Total available-for-sale marketable debt securities	$	106,637	$	111,325

- Definition

Tabular disclosure of available-for-sale securities which includes, but is not limited to, changes in the cost basis and fair value, fair value and gross unrealized gain (loss), fair values by type of security, contractual maturity and classification, amortized cost basis, contracts to acquire securities to be accounted for as available-for-sale, debt maturities, transfers to trading, change in net unrealized holding gain (loss) net of tax, continuous unrealized loss position fair value, aggregate losses qualitative disclosures, other than temporary impairment (OTTI) losses or other disclosures related to available for sale securities.

+ References + Details

Fair Value Measurements (Tables)

6 Months Ended

Jun. 30, 2017

Fair Value Disclosures [Abstract]

Schedule of Fair Value of Company's Financial Assets and Liabilities

The following table presents the fair value of the Company’s financial assets and liabilities determined using the inputs defined above (amounts in thousands).

	June 30, 2017
	Level 1		Level 2		Level 3		Total
Assets
Money market funds	$	13,059	$	—	$	—	$	13,059
U.S. government securities		—		32,892		—		32,892
Corporate notes		—		24,258		—		24,258
Commercial paper		—		36,428		—		36,428
Total	$	13,059	$	93,578	$	—	$	106,637

	December 31, 2016
	Level 1		Level 2		Level 3		Total
Assets
Money market funds	$	45,937	$	—	$	—	$	45,937
U.S. government securities		—		16,490		—		16,490
Corporate notes		—		23,927		—		23,927
Commercial paper		—		24,971		—		24,971
Total	$	45,937	$	65,388	$	—	$	111,325

Summary of Changes in Fair Value of Preferred Stock Warrants Classified as Level 3

The following table sets forth a summary of the changes in the fair value of the preferred stock warrants which is classified as Level 3 in the fair value hierarchy.

	Six Months Ended June 30, 2017		Six Months Ended June 30, 2016
Beginning balance	$	—	$	2,949
Total change in fair value recorded as other expense, net		—		397
Ending balance	$	—	$	3,346

- Definition

Tabular disclosure of financial instruments measured at fair value, including those classified in shareholders' equity measured on a recurring or nonrecurring basis. Disclosures include, but are not limited to, fair value measurements recorded and the reasons for the measurements, level within the fair value hierarchy in which the fair value measurements are categorized and transfers between levels 1 and 2. Nonrecurring fair value measurements are those that are required or permitted in the statement of financial position in particular circumstances.

+ References + Details

Balance Sheet Components (Tables)

6 Months Ended

Jun. 30, 2017

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Components of Inventory and PCBAs

Inventory and PCBAs consisted of the following (in thousands):

	June 30, 2017		December 31, 2016
Raw materials	$	1,051	$	839
Finished goods		3,411		3,324
Total	$	4,462	$	4,163

Reported on the consolidated balance sheet as:
Inventory	$	1,231	$	1,390
Other assets		3,231		2,773
Total	$	4,462	$	4,163

Components of Property and Equipment, Net

Property and equipment, net consisted of the following (in thousands):

	June 30,			December 31,
	2017			2016
Laboratory and manufacturing equipment	$	1,896		$	1,509
Computer equipment and software		842			736
Furniture and fixtures		679			657
Leasehold improvements		733			502
Internal-use software		4,302			2,900
Total property and equipment, gross		8,452			6,304
Less: accumulated depreciation and amortization		(2,286	)		(1,651	)
Total property and equipment, net	$	6,166		$	4,653

Components of Accrued Liabilities

Accrued liabilities consisted of the following (in thousands):

	June 30,		December 31,
	2017		2016
Accrued vacation	$	1,988	$	1,642
Accrued payroll and related expenses		4,970		6,179
Accrued ESPP contributions		232		417
Accrued professional services fees		1,152		636
Other		1,643		1,291
Total accrued liabilities	$	9,985	$	10,165

Commitments and Contingencies (Tables)

6 Months Ended

Jun. 30, 2017

Commitments And Contingencies Disclosure [Abstract]

Schedule of Future Minimum Lease Payments Under Non-cancelable Operating Leases

The following table summarizes the Company’s future minimum lease payments as of June 30, 2017 (in thousands):

Period Ending December 31:
2017 (remainder of year)	$	2,491
2018		5,089
2019		5,108
2020		1,178
2021		406
Thereafter		2,541
Total	$	16,813

Stockholders' Equity (Tables)

6 Months Ended

Jun. 30, 2017

Equity [Abstract]

Schedule of Common Stock Shares Reserved for Future Issuance

The Company had reserved shares of common stock for issuance as follows:

	June 30,		December 31,
	2017		2016
Options issued and outstanding		3,107,386		2,977,218
Unvested restricted stock units		366,684		105,529
Common stock warrants issued and outstanding		143,795		217,245
Shares available for grant under future stock plans		4,893,448		4,226,068
		8,511,313		7,526,060

- Definition

Tabular disclosure of an entity's stock, including par or stated value per share, number and dollar amount of share subscriptions, shares authorized, shares issued, shares outstanding, number and dollar amount of shares held in an employee trust, dividend per share, total dividends, share conversion features, par value plus additional paid in capital, the value of treasury stock and other information necessary to a fair presentation, and EPS information. Stock by class includes common, convertible, and preferred stocks which are not redeemable or redeemable solely at the option of the issuer. Includes preferred stock with redemption features that are solely within the control of the issuer and mandatorily redeemable stock if redemption is required to occur only upon liquidation or termination of the reporting entity. If more than one issue is outstanding, state the title of each issue and the corresponding dollar amount; dollar amount of any shares subscribed but unissued and the deduction of subscriptions receivable there from; number of shares authorized, issued, and outstanding.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
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Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 480
-SubTopic 10
-Section S99
-Paragraph 1
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Reference 3: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
-Topic 235
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-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(d))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

Reference 4: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(29))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 5: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
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Reference 6: http://www.xbrl.org/2003/role/presentationRef
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Reference 7: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
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Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=65888546&loc=d3e21300-112643

Reference 10: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
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-Subparagraph (SX 210.5-02(27))
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-Name Accounting Standards Codification
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+ Details

Stock Incentive Plans (Tables)

6 Months Ended

Jun. 30, 2017

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Summary of Share-based Awards Available for Grant under 2016 Plan

A summary of share-based awards available for grant under the 2016 Plan is as follows:

	Options Available for Grant
Balance at December 31, 2015		331,938
Additional options authorized		3,865,000
Options granted		(466,914	)
Options forfeited		13,013
Balance at December 31, 2016		3,743,037
Additional options authorized		1,106,966
Options granted		(675,071	)
Options forfeited		8,523
Balance at June 30, 2017		4,183,455

Summary of Stock Option Activity Under 2006 and 2016 Plans, Including Grants to Non-employees

The following table summarizes stock option activity under the 2006 and 2016 Plans, including grants to non-employees:

				Options Outstanding
	Options Outstanding			Weighted- Average Exercise Price Per Share		Weighted- Average Remaining Contractual Life (years)		Aggregate Intrinsic Value (in thousands)
Balances at December 31, 2015		2,685,913		$	4.81		7.63	$	11,589
Options granted		361,385			15.65
Options exercised		(57,067	)		2.33
Options forfeited		(13,013	)		6.92
Balances at December 31, 2016		2,977,218			6.16		6.93	$	70,979
Options granted		411,183			35.59
Options exercised		(272,492	)		3.08
Options forfeited		(8,523	)		18.53
Balances at June 30, 2017		3,107,386		$	10.29		7.29	$	100,068
Options exercisable – June 30, 2017		1,886,915		$	4.79		6.28	$	71,128
Options vested and expected to vest – June 30, 2017		3,028,901		$	9.97		7.24	$	98,486

Stock-Based Compensation (Tables)

6 Months Ended

Jun. 30, 2017

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Schedule of Fair Value of Employee and Director Stock Options Estimated Using Weighted Average Assumptions

The fair value of employee and director stock options was estimated at the date of grant using a Black-Scholes option valuation model with the weighted average assumptions below.

	Three Months Ended June 30						Six Months Ended June 30
	2017			2016			2017			2016
Expected term (in years)		6.1			6.1			6.1			6.1
Expected volatility		48.1	%		60.0	%		52.6	%		60.0	%
Risk-free interest rate		2.00	%		1.52	%		2.08	%		1.48	%
Dividend yield		0.0	%		0.0	%		0.0	%		0.0	%

Summary of Total Stock-Based Compensation Expense Included in Statements of Operations and Comprehensive Loss

The following table summarizes the total stock-based compensation expense included in the statements of operations and comprehensive loss for all periods presented (in thousands):

	Three Months Ended June 30				Six Months Ended June 30
	2017		2016		2017		2016
Cost of revenue	$	38	$	3	$	76	$	5
Research and development		383		33		752		69
Selling, general and administrative		1,844		407		3,464		776
Total stock-based compensation expense	$	2,265	$	443	$	4,292	$	850

Net Loss Per Common Share (Tables)

6 Months Ended

Jun. 30, 2017

Earnings Per Share [Abstract]

Computation of Basic and Diluted Net Loss per Share Attributable to Common Stockholders

The following table sets forth the computation of the basic and diluted net loss per share attributable to common stockholders (in thousands, except share and per share data):

	Three Months Ended June 30,						Six Months Ended June 30,
	2017			2016			2017			2016
Numerator:
Net loss	$	(6,444	)	$	(4,436	)	$	(11,747	)	$	(10,562	)
Denominator:
Weighted-average shares used to compute net loss per common share, basic and diluted		22,362,608			1,435,483			22,257,849			1,424,278
Net loss per common share, basic and diluted	$	(0.29	)	$	(3.09	)	$	(0.53	)	$	(7.42	)

Schedule of Anti-dilutive Securities Excluded from Diluted Net Loss per Common Share

	As of June 30,
	2017		2016
Convertible preferred stock on an as-if converted basis		—		13,343,981
Options to purchase common stock		3,107,386		2,722,648
RSUs issued and unvested		366,684		—
Warrants to purchase convertible preferred stock on an as-if converted basis		—		328,114
Warrants to purchase common stock		143,795		—
Total		3,617,865		16,394,743

Organization and Description of Business - Additional Information (Details) $ in Millions				6 Months Ended
	Oct. 31, 2016 USD ($) shares	Oct. 19, 2016 USD ($) shares	Oct. 05, 2016	Jun. 30, 2017
Class Of Stock [Line Items]
Reverse stock split description				On October 4, 2016, the Company’s board of directors approved an amendment to the Company’s amended and restated certificate of incorporation to effect a reverse split of the Company’s issued and outstanding common stock at a 1-for-5.882698 ratio, which was effected on October 5, 2016.
Common stock, reverse stock split ratio			5.882698
Common stock issued \| shares		7,238,235
Initial public offering closing date		Oct. 25, 2016
Proceeds from stock issuance, net of underwriting discounts and commissions		$ 110.7
Underwriting discounts and commissions		8.6
Other expenses		$ 3.7
Redeemable Convertible Preferred Stock \| IPO
Class Of Stock [Line Items]
Number of shares converted into common stock \| shares	13,375,333
Carrying value of convertible preferred stock converted into common stock	$ 97.6

Summary of Significant Accounting Policies - Schedule of Changes in Allowance for Doubtful Accounts (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2017	Dec. 31, 2016
Receivables [Abstract]
Balance, beginning of period	$ 1,792	$ 1,125
Add: provision for doubtful accounts	1,426	1,960
Less: write-offs, net of recoveries and other adjustments	(378)	(1,293)
Balance, end of period	$ 2,840	$ 1,792

Summary of Significant Accounting Policies - Schedule of Changes in Contractual Allowance (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2017	Dec. 31, 2016
Receivables [Abstract]
Balance, beginning of period	$ 2,340	$ 338
Add: contractual allowances	2,790	2,726
Less: write-offs, net of recoveries and other adjustments	(96)	(724)
Balance, end of period	$ 5,034	$ 2,340

Summary of Significant Accounting Policies - Additional Information (Details) - USD ($)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Summary Of Significant Accounting Policies [Line Items]
Impairment long-lived assets			$ 0
Income tax position likely of being realized upon ultimate settlement			greater than 50%
Unrecognized tax benefits, income tax interest or penalties charge			$ 0
ASU No. 2016-09
Summary Of Significant Accounting Policies [Line Items]
Increase in NOL related to deferred tax assets			$ 100,000
ZIO Event Card
Summary Of Significant Accounting Policies [Line Items]
Equipment wear period			30 days
Internal-Use Software
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life			5 years
Printed Circuit Board Assemblies
Summary Of Significant Accounting Policies [Line Items]
Total other assets	$ 3,200,000		$ 3,200,000		$ 2,800,000
Minimum
Summary Of Significant Accounting Policies [Line Items]
Property and equipment, estimated useful life			3 years
Maximum
Summary Of Significant Accounting Policies [Line Items]
Property and equipment, estimated useful life			5 years
Maximum \| ZIO Patch Service
Summary Of Significant Accounting Policies [Line Items]
Equipment wear period			14 days
Revenue \| Customer Concentration Risk \| Government Agencies
Summary Of Significant Accounting Policies [Line Items]
Concentration of credit risk	38.00%	37.00%	41.00%	41.00%
Accounts Receivable \| Accounts Receivable Concentration Risk \| Government Agencies
Summary Of Significant Accounting Policies [Line Items]
Concentration of credit risk			16.00%		27.00%
Revenue Related to Non-contracted Claims
Summary Of Significant Accounting Policies [Line Items]
Revenue recognized	$ 2,800,000	$ 2,400,000	$ 5,700,000	$ 4,300,000
Contracted Revenue Recognized on Accrual Basis
Summary Of Significant Accounting Policies [Line Items]
Revenue recognized	$ 21,100,000	$ 13,300,000	$ 39,600,000	$ 24,300,000

Cash Equivalents and Investments - Schedule of Fair Value of Securities, not Including Cash (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Cash And Cash Equivalents [Line Items]
Amortized Cost	$ 106,687	$ 111,334
Gross Unrealized Gains	1	11
Gross Unrealized Losses	(51)	(20)
Estimated Fair Value	106,637	111,325
Cash equivalents	13,059	45,937
Short-term investments	93,578	54,407
Long-term investments		10,981
Total cash equivalents and investments	106,637	111,325
Money Market Funds
Cash And Cash Equivalents [Line Items]
Amortized Cost	13,059	45,937
Estimated Fair Value	13,059	45,937
U.S. Government Securities
Cash And Cash Equivalents [Line Items]
Amortized Cost	32,937	16,479
Gross Unrealized Gains		11
Gross Unrealized Losses	(45)
Estimated Fair Value	32,892	16,490
Commercial Paper
Cash And Cash Equivalents [Line Items]
Amortized Cost	36,428	24,971
Estimated Fair Value	36,428	24,971
Corporate Notes
Cash And Cash Equivalents [Line Items]
Amortized Cost	24,263	23,947
Gross Unrealized Gains	1
Gross Unrealized Losses	(6)	(20)
Estimated Fair Value	$ 24,258	$ 23,927

Cash Equivalents and Investments - Schedule of Fair Value of Short-term and Long-term Investments Classified by Maturity (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Marketable Securities [Abstract]
Due within one year	$ 106,637	$ 100,344
Due after one year through three years		10,981
Total available-for-sale marketable debt securities	$ 106,637	$ 111,325

- Definition

Investments in debt and equity securities which are categorized neither as held-to-maturity nor trading and which are intended to be sold or mature more than one year from the balance sheet date or operating cycle, if longer. Such securities are reported at fair value; unrealized gains (losses) related to Available-for-sale Securities are excluded from earnings and reported in a separate component of shareholders' equity (other comprehensive income), unless the Available-for-sale security is designated as a hedge or is determined to have had an other than temporary decline in fair value below its amortized cost basis. All or a portion of the unrealized holding gain (loss) of an Available-for-sale security that is designated as being hedged in a fair value hedge is recognized in earnings during the period of the hedge, as are other than temporary declines in fair value below the cost basis for investments in equity securities and debt securities that an entity intends to sell or it is more likely than not that it will be required to sell before the recovery of its amortized cost basis. Other than temporary declines in fair value below the cost basis for debt securities categorized as Available-for-sale that an entity does not intend to sell and for which it is not more likely than not that the entity will be required to sell before the recovery of its amortized cost basis are bifurcated into credit losses and losses related to all other factors. Other than temporary declines in fair value below cost basis related to credit losses are recognized in earnings, and losses related to all other factors are recognized in other comprehensive income.

+ References + Details

Fair Value Measurements - Schedule of Fair Value of Company's Financial Assets and Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Assets
Total financial assets	$ 106,637	$ 111,325
Level 1
Assets
Total financial assets	13,059	45,937
Level 2
Assets
Total financial assets	93,578	65,388
Money Market Funds
Assets
Total financial assets	13,059	45,937
Money Market Funds \| Level 1
Assets
Total financial assets	13,059	45,937
U.S. Government Securities
Assets
Total financial assets	32,892	16,490
U.S. Government Securities \| Level 2
Assets
Total financial assets	32,892	16,490
Corporate Notes
Assets
Total financial assets	24,258	23,927
Corporate Notes \| Level 2
Assets
Total financial assets	24,258	23,927
Commercial Paper
Assets
Total financial assets	36,428	24,971
Commercial Paper \| Level 2
Assets
Total financial assets	$ 36,428	$ 24,971

Fair Value Measurements - Additional Information (Details)	6 Months Ended
	Jun. 30, 2017 USD ($)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Abstract]
Fair value measurement, liability transfers into level 3, amount	$ 0
Fair value measurement, liability transfers out of level 3, amount	$ 0

Fair Value Measurements - Summary of Changes in Fair Value of Preferred Stock Warrants Classified as Level 3 (Details) - Level 3 - Preferred Stock Warrant Liabilities $ in Thousands	6 Months Ended
	Jun. 30, 2016 USD ($)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Beginning balance	$ 2,949
Total change in fair value recorded as other expense, net	397
Ending balance	$ 3,346

Balance Sheet Components - Components of Inventory and PCBAs (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Inventory [Line Items]
Total inventory and printed circuit board assemblies	$ 4,462	$ 4,163
Inventory	1,231	1,390
Other assets	3,531	3,052
PCBA
Inventory [Line Items]
Other assets	3,231	2,773
Raw Materials
Inventory [Line Items]
Total inventory and printed circuit board assemblies	1,051	839
Finished Goods
Inventory [Line Items]
Total inventory and printed circuit board assemblies	$ 3,411	$ 3,324

Balance Sheet Components - Components of Property and Equipment, Net (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Property Plant And Equipment [Line Items]
Total property and equipment, gross	$ 8,452	$ 6,304
Less: accumulated depreciation and amortization	(2,286)	(1,651)
Total property and equipment, net	6,166	4,653
Laboratory and Manufacturing Equipment
Property Plant And Equipment [Line Items]
Total property and equipment, gross	1,896	1,509
Computer Equipment and Software
Property Plant And Equipment [Line Items]
Total property and equipment, gross	842	736
Furniture and Fixtures
Property Plant And Equipment [Line Items]
Total property and equipment, gross	679	657
Leasehold Improvements
Property Plant And Equipment [Line Items]
Total property and equipment, gross	733	502
Internal-Use Software
Property Plant And Equipment [Line Items]
Total property and equipment, gross	$ 4,302	$ 2,900

Balance Sheet Components - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Property Plant And Equipment [Abstract]
Depreciation and amortization expense	$ 300	$ 200	$ 635	$ 436

Balance Sheet Components - Components of Accrued Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Payables And Accruals [Abstract]
Accrued vacation	$ 1,988	$ 1,642
Accrued payroll and related expenses	4,970	6,179
Accrued ESPP contributions	232	417
Accrued professional services fees	1,152	636
Other	1,643	1,291
Total accrued liabilities	$ 9,985	$ 10,165

Related-Party Transactions - Additional Information (Details) - Kaiser - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Related Party Transaction [Line Items]
Revenue recognized	$ 1.0	$ 0.6	$ 1.8	$ 1.4
Amounts receivable from transaction	0.5		0.5		$ 0.4
Service related expenses	0.3	$ 0.2	0.3	$ 0.3
Accounts payable and accrued liabilities	$ 0.1		$ 0.1		$ 0.2
Convertible Preferred Stock
Related Party Transaction [Line Items]
Convertible preferred stock, ownership percentage					6.10%

Commitments and Contingencies - Future Minimum Lease Payments Under Non-cancelable Operating Leases (Details) $ in Thousands	Jun. 30, 2017 USD ($)
Operating Leases Future Minimum Payments Due [Abstract]
2017 (remainder of year)	$ 2,491
2018	5,089
2019	5,108
2020	1,178
2021	406
Thereafter	2,541
Total	$ 16,813

Debt - Additional Information (Details)	1 Months Ended				6 Months Ended	12 Months Ended
Debt - Additional Information (Details)	Jun. 30, 2017 USD ($)	Dec. 31, 2015 USD ($) Tranche	Jun. 30, 2014 USD ($) $ / shares shares	Nov. 30, 2012 USD ($) shares	Jun. 30, 2017 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2016 USD ($)	Dec. 01, 2016 USD ($)	Aug. 31, 2016 USD ($)	Dec. 04, 2015 USD ($)	Jun. 30, 2015 $ / shares shares
Series D Preferred Stock
Debt Instrument [Line Items]
Warrants issued to purchase shares \| shares			20,136
Exercise price of warrants \| $ / shares			$ 7.31
CHCF Note
Debt Instrument [Line Items]
Debt instrument maturity date				Nov. 30, 2016
Debt balance	$ 1,500,000				$ 1,500,000		$ 1,500,000
Proceeds from long-term debt, net of issuance costs				$ 1,500,000
Debt instrument accrues simple interest rate				2.00%
Debt instrument extended maturity date					May 31, 2018
CHCF Note \| Series D Preferred Stock
Debt Instrument [Line Items]
Warrants issued to purchase shares \| shares				22,807							8,552
Exercise price of warrants \| $ / shares											$ 6.58
Pharmakon Loan Agreement
Debt Instrument [Line Items]
Maximum borrowing capacity		$ 55,000,000
Number of tranches for loans \| Tranche		2
Paid in kind, interest percentage					50.00%
Debt instrument, covenant description					The Company is subject to a financial covenant related to minimum trailing revenue targets that begins in June 2017, and is tested on a semi-annual basis. The minimum net revenue covenant ranges from $44.7 million for the period ended June 30, 2017 to $102.6 million for the period ended December 31, 2021, which was achieved as of June 30, 2017. The minimum net revenues financial covenant has a 45-day equity cure period following required delivery date of the financial statements.
Debt instrument, covenant compliance minimum net revenue target next twelve months	44,700,000
Debt instrument, covenant equity cure period					45 days
Debt instrument maturity date					Dec. 31, 2021
Debt balance	$ 31,600,000				$ 31,600,000		30,800,000
Pharmakon Loan Agreement \| Silicon Valley Bank
Debt Instrument [Line Items]
Repayment of bank debt		$ 4,900,000
Pharmakon Loan Agreement \| Scenario Forecast
Debt Instrument [Line Items]
Debt instrument, covenant compliance minimum net revenue fifth year						$ 102,600,000
Pharmakon Loan Agreement \| Tranche A Loans
Debt Instrument [Line Items]
Maximum borrowing capacity										$ 30,000,000
Debt instrument, fixed interest rate	9.50%				9.50%
Debt instrument, periodic payment					quarterly
Debt instrument, interest due and payable	50.00%				50.00%
Pharmakon Loan Agreement \| Tranche B Loans
Debt Instrument [Line Items]
Maximum borrowing capacity								$ 25,000,000
Loan and Security Agreement
Debt Instrument [Line Items]
Proceeds from long-term debt, net of issuance costs			$ 4,900,000
Debt borrowed additional advance			$ 5,000,000
Repayment of debt		4,900,000
Loan and Security Agreement \| Series D Preferred Stock
Debt Instrument [Line Items]
Warrants issued to purchase shares \| shares			20,136
Exercise price of warrants \| $ / shares			$ 7.31
Warrants expiry period					2024-06
SVB Loan Agreement
Debt Instrument [Line Items]
Maximum borrowing capacity		$ 15,000,000
Credit facility expiration date					Dec. 04, 2018
Debt instrument variable rate basis trailing period of revenue		6 months
Borrowing capacity description					Any principal amount outstanding under the SVB revolving credit line shall bear interest at a floating rate per annum equal to the rate published by The Wall Street Journal as the “Prime Rate” plus 0.25%, are tied to the Company’s trailing six-month revenue and subject to certain revenue targets. The Company may borrow up to 80% of its eligible accounts receivable, up to the maximum of $15.0 million.
SVB Loan Agreement \| San Francisco Office \| Standby Letters of Credit
Debt Instrument [Line Items]
Letter of credit									$ 3,100,000
SVB Loan Agreement \| Maximum
Debt Instrument [Line Items]
Percentage of eligible accounts receivable for borrowings		80.00%
Credit facility borrowing capacity	$ 8,100,000				$ 8,100,000		$ 2,500,000
SVB Loan Agreement \| Prime Rate
Debt Instrument [Line Items]
Debt instrument interest rate spread		0.25%

Income Taxes - Additional Information (Details) - USD ($)	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Provision or benefit for income taxes	$ 0	$ 0
Benefit recognized for net operating loss carryforwards	0
Benefit recognized for other deferred tax assets	$ 0
Unrecognized tax benefit			$ 600,000
Unrecognized tax benefit that affects effective tax rate			$ 0

Stockholders' Equity - Additional Information (Details) - USD ($)	6 Months Ended
	Jun. 30, 2017	Dec. 31, 2016
Equity [Abstract]
Common stock, shares authorized	100,000,000	100,000,000
Common stock, par value	$ 0.001	$ 0.001
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, par value	$ 0.001	$ 0.001
Dividends declared	$ 0

Stockholders' Equity - Schedule Of Common Stock Shares Reserved For Future Issuance (Details) - shares	Jun. 30, 2017	Dec. 31, 2016
Class Of Stock [Line Items]
Total number of shares reserved for future issuance	8,511,313	7,526,060
Common stock warrants issued and outstanding
Class Of Stock [Line Items]
Total number of shares reserved for future issuance	143,795	217,245
Options Issued and Outstanding
Class Of Stock [Line Items]
Total number of shares reserved for future issuance	3,107,386	2,977,218
Unvested restricted stock units
Class Of Stock [Line Items]
Total number of shares reserved for future issuance	366,684	105,529
Shares Available for Grant Under Future Stock Plans
Class Of Stock [Line Items]
Total number of shares reserved for future issuance	4,893,448	4,226,068

Preferred Stock Warrant Liabilities - Additional Information (Details) - USD ($)			1 Months Ended		3 Months Ended	6 Months Ended
	May 02, 2017	Oct. 26, 2016	Jun. 30, 2014	Nov. 30, 2012	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Mar. 27, 2013
Class Of Warrant Or Right [Line Items]
Change in fair value of preferred stock warrant liabilities							$ 397,000
Series D Preferred Stock
Class Of Warrant Or Right [Line Items]
Warrants issued to purchase shares			20,136
Exercise price of warrants			$ 7.31
Change in fair value of preferred stock warrant liabilities					$ 1,000		(26,000)
Warrants expiry period						2024-06
Warrant exercised	10,068	10,068
Warrant exercise period	May 02, 2017	Oct. 26, 2016
Issuance of common stock upon exercise of warrants, Shares	8,077	7,310
Series D Preferred Stock \| Warrant
Class Of Warrant Or Right [Line Items]
Fair value assumptions, discount rate			30.00%
Fair value warrants recorded as debt discount			$ 98,000
2012 Loan Agreement \| Series D Preferred Stock
Class Of Warrant Or Right [Line Items]
Warrants issued to purchase shares								207,177
Change in fair value of preferred stock warrant liabilities					$ 59,000		$ (235,000)
Warrant outstanding						143,795
2012 Loan Agreement \| Series C Preferred Stock
Class Of Warrant Or Right [Line Items]
Exercise price of warrants				$ 0.001
Warrants term				7 years

Stock Incentive Plans - Additional Information (Details)	1 Months Ended	6 Months Ended		12 Months Ended
	Oct. 31, 2016 shares	Jun. 30, 2017 Period $ / shares shares	Jun. 30, 2016 $ / shares	Dec. 31, 2016 shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options granted during the period		411,183		361,385
Shares available for future issuance		8,511,313		7,526,060
Estimated weighted-average grant date fair value of common stock underlying options granted \| $ / shares		$ 18.33	$ 5.75
2006 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock option plan, description		Options under the Plan were granted for periods of up to ten years and at the fair value of the shares on the date of grant as determined by the board of directors.
Stock option vesting term		3 years
2006 Equity Incentive Plan \| First Anniversary of Grant
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock option exercisable rate, Percentage		25.00%
2006 Equity Incentive Plan \| Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock option, period for grant		10 years
2006 Equity Incentive Plan \| Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of voting power of all classes of stock		10.00%
2006 Equity Incentive Plan \| ISO \| Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock option vesting term		5 years
2006 Equity Incentive Plan \| Other Options \| Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock option vesting term		10 years
2016 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock option plan, description		On the first day of each year beginning with 2017, the 2016 Plan authorizes an annual increase of the least of 3,865,000 shares, 5% of outstanding common stock on the last day of the immediately preceding fiscal year or an amount as determined by the Company's Board of Directors.
Effective date		Oct. 19, 2016
Options granted during the period	0
Shares available for future issuance	3,865,000	4,971,966
Percentage of outstanding common stock increased annually under the plan	5.00%
2016 Plan \| Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock option, period for grant		10 years
2016 Plan \| Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of stock option exercise price of fair market value of common stock	100.00%
Employee Stock Purchase Program (“ESPP”)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Effective date		Oct. 19, 2016
Shares available for future issuance	483,031	709,993
Percentage of outstanding common stock increased annually under the plan	1.50%
Increase in shares available for future issuance	966,062
Offering period		12 months
Number of purchase period \| Period		2
Purchase period		6 months
Percentage of employee purchase shares of fair market value	85.00%
Common stock issued to employees		105,128
Employee Stock Purchase Program (“ESPP”) \| Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of payroll deductions of eligible compensation	15.00%

Stock Incentive Plans - Summary of Share-based Awards Available for Grant under 2016 Plan (Details) - shares	6 Months Ended	12 Months Ended
	Jun. 30, 2017	Dec. 31, 2016
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options Available for Grant, Options forfeited	8,523	13,013
2016 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options Available for Grant, Beginning balance	3,743,037	331,938
Options Available for Grant, Additional options authorized	1,106,966	3,865,000
Options Available for Grant, Options granted	(675,071)	(466,914)
Options Available for Grant, Options forfeited	8,523	13,013
Options Available for Grant, Ending balance	4,183,455	3,743,037

Stock Incentive Plans - Summary of Stock Option Activity Under 2006 and 2016 Plans, Including Grants to Non-employees (Details) - USD ($) $ / shares in Units, $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2017	Dec. 31, 2016	Dec. 31, 2015
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Options Outstanding, Beginning balance	2,977,218	2,685,913
Options granted	411,183	361,385
Options exercised	(272,492)	(57,067)
Options forfeited	(8,523)	(13,013)
Options Outstanding, Ending balance	3,107,386	2,977,218	2,685,913
Options exercisable	1,886,915
Options vested and expected to vest	3,028,901
Options Outstanding, Weighted Average Exercise Price Per Share, Beginning Balance	$ 6.16	$ 4.81
Options Outstanding, Weighted Average Exercise Price Per Share, Options granted	35.59	15.65
Options Outstanding, Weighted Average Exercise Price Per Share, Options exercised	3.08	2.33
Options Outstanding, Weighted Average Exercise Price Per Share, Options forfeited	18.53	6.92
Options Outstanding, Weighted Average Exercise Price Per Share, Ending Balance	10.29	$ 6.16	$ 4.81
Options Outstanding, Weighted Average Exercise Price Per Share, Exercisable	4.79
Options Outstanding, Weighted Average Exercise Price Per Share, vested and expected to vest	$ 9.97
Options Outstanding, Weighted- Average Remaining Contractual Life (years)	7 years 3 months 15 days	6 years 11 months 5 days	7 years 7 months 17 days
Options exercisable, Weighted- Average Remaining Contractual Life (years)	6 years 3 months 11 days
Options vested and expected to vest, Weighted- Average Remaining Contractual Life (years)	7 years 2 months 27 days
Options Outstanding, Aggregate Intrinsic Value	$ 100,068	$ 70,979	$ 11,589
Options exercisable, Aggregate Intrinsic Value	71,128
Options vested and expected to vest, Aggregate Intrinsic Value	$ 98,486

Stock-Based Compensation - Schedule of Fair Value of Employee and Director Stock Options Estimated Using Weighted Average Assumptions (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Expected term (in years)	6 years 1 month 6 days	6 years 1 month 6 days	6 years 1 month 6 days	6 years 1 month 6 days
Expected volatility	48.10%	60.00%	52.60%	60.00%
Risk-free interest rate	2.00%	1.52%	2.08%	1.48%
Dividend yield	0.00%	0.00%	0.00%	0.00%

Stock-Based Compensation - Summary of Total Stock-Based Compensation Expense Included in Statements of Operations and Comprehensive Loss (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	$ 2,265	$ 443	$ 4,292	$ 850
Cost of Revenue
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	38	3	76	5
Research and development
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	383	33	752	69
Selling, general and administrative
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	$ 1,844	$ 407	$ 3,464	$ 776

Stock-Based Compensation - Additional Information (Details) $ in Millions	6 Months Ended
	Jun. 30, 2017 USD ($)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total unamortized compensation costs, net of estimated forfeitures related to unvested stock options	$ 10.1
Unamortized compensation costs related to unvested stock options, expected period of recognition	2 years 8 months 12 days
Restricted Stock Units ("RSUs")
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total unamortized compensation costs, net of estimated forfeitures related to unvested stock options	$ 9.4
Unamortized compensation costs related to unvested stock options, expected period of recognition	3 years
ESPP
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total unamortized compensation costs, net of estimated forfeitures related to unvested stock options	$ 0.9
Unamortized compensation costs related to unvested stock options, expected period of recognition	10 months 24 days

Net Loss Per Common Share - Computation of Basic and Diluted Net Loss per Share Attributable to Common Stockholders (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Numerator:
Net Loss	$ (6,444)	$ (4,436)	$ (11,747)	$ (10,562)
Denominator:
Weighted-average shares used to compute net loss per common share, basic and diluted	22,362,608	1,435,483	22,257,849	1,424,278
Net loss per common share, basic and diluted	$ (0.29)	$ (3.09)	$ (0.53)	$ (7.42)

Net Loss Per Common Share - Schedule of Anti-dilutive Securities Excluded from Diluted Net Loss per Common Share (Details) - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from diluted net loss per common share	3,617,865	16,394,743	3,617,865	16,394,743
Convertible Preferred Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from diluted net loss per common share		13,343,981		13,343,981
Options to Purchase Common Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from diluted net loss per common share	3,107,386	2,722,648	3,107,386	2,722,648
Restricted Stock Units ("RSUs")
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from diluted net loss per common share	366,684		366,684
Warrants to Purchase Convertible Preferred Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from diluted net loss per common share		328,114		328,114
Warrants to Purchase Common Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from diluted net loss per common share	143,795		143,795

Cash Equivalents and Investments - Additional Information (Details)	6 Months Ended
	Jun. 30, 2017
Cash And Cash Equivalents [Abstract]
Available-for-sale securities, weighted average days to maturity	126 days