GenMark Diagnostics (GNMK) 10-Q 30 Apr 19 2019 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2019	Apr. 25, 2019
Document and Entity Information [Abstract]
Entity Registrant Name	GenMark Diagnostics, Inc.
Entity Central Index Key	0001487371
Current Fiscal Year End Date	--03-31
Entity Filer Category	Accelerated Filer
Document Type	10-Q
Document Period End Date	Mar. 31, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q1
Amendment Flag	false
Entity Common Stock, Shares Outstanding		57,028,553

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($)	Mar. 31, 2019	Dec. 31, 2018
Current Assets:
Cash and cash equivalents	$ 35,304,000	$ 36,286,000
Short-term marketable securities	13,118,000	8,882,000
Accounts receivable, net of allowances of $75 and $2,754, respectively	9,168,000	11,534,000
Inventories	9,391,000	10,244,000
Operating Lease, Right-of-Use Asset	1,260,000	0
Prepaid expenses and other current assets	1,396,000	1,483,000
Total current assets	69,637,000	68,429,000
Property and equipment, net	19,927,000	21,070,000
Intangible assets, net	1,875,000	2,023,000
Restricted cash	758,000	758,000
NoncurrentOperatingLeaseRightOfUseAsset	3,734,000	0
Other long-term assets	729,000	701,000
Total assets	96,660,000	92,981,000
Current liabilities:
Accounts payable	8,508,000	9,886,000
Accrued compensation	5,111,000	7,358,000
Operating Lease, Liability, Current	1,801,000	0
Other current liabilities	2,321,000	3,043,000
Total current liabilities	17,741,000	20,287,000
Deferred rent	0	2,996,000
Long-term debt	47,821,000	36,042,000
Operating Lease, Liability, Noncurrent	6,591,000	0
Other noncurrent liabilities	70,000	109,000
Total liabilities	72,223,000	59,434,000
Stockholders' equity:
Preferred stock, $0.0001 par value; 5,000 authorized, none issued	0	0
Common stock, $0.0001 par value; 100,000 authorized; 55,955 and 55,066 shares issued and outstanding, respectively	6,000	6,000
Additional paid-in capital	503,318,000	500,344,000
Accumulated deficit	(478,963,000)	(466,883,000)
Accumulated other comprehensive income	76,000	80,000
Total stockholders’ equity	24,437,000	33,547,000
Total liabilities and stockholders’ equity	$ 96,660,000	$ 92,981,000

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Statement of Financial Position [Abstract]
Accounts receivable - net of allowance	$ 75	$ 75
Preferred stock, par value	$ 0.0001	$ 0.0001
Preferred stock, authorized	5,000,000	5,000,000
Preferred stock, issued	0	0
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, authorized	100,000,000	100,000,000
Common stock, issued	57,026,000	56,240,000
Common stock, outstanding	57,026,000	56,240,000

Condensed Consolidated Statemen

Condensed Consolidated Statements of Comprehensive Loss (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Revenue:
Product revenue	$ 21,371	$ 20,576
License and other revenue	162	69
Total revenue	21,533	20,645
Cost of revenue	15,670	16,480
Gross profit	5,863	4,165
Operating expenses:
Sales and marketing	5,909	5,402
General and administrative	4,521	4,133
Research and development	6,343	5,420
Total operating expenses	16,773	14,955
Loss from operations	(10,910)	(10,790)
Other income (expense):
Interest income	133	187
Interest expense	(1,276)	(788)
Other income (expense)	(11)	(12)
Total other income (expense)	(1,154)	(613)
Loss before provision for income taxes	(12,064)	(11,403)
Income tax expense (benefit)	16	20
Net loss	$ (12,080)	$ (11,423)
Net loss per share, basic and diluted	$ (0.21)	$ (0.21)
Weighted average number of shares outstanding, basic and diluted	56,581	55,205
Other comprehensive loss:
Net loss	$ 12,080	$ 11,423
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax	(6)	34
Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Net of Tax	2	8
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	(4)	42
Other Comprehensive Income (Loss), Net of Tax	$ (12,084)	$ (11,381)

Condensed Consolidated Statem_2

Condensed Consolidated Statement of Cash Flows (Unaudited) - USD ($)	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Operating activities:
Net loss	$ 12,080,000	$ 11,423,000
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	1,812,000	1,740,000
Net amortization/(accretion) of premiums/discounts on investments	(21,000)	(42,000)
Amortization of deferred debt issuance costs	366,000	290,000
Stock-based compensation	2,544,000	2,724,000
Non-cash inventory adjustments	634,000	449,000
Other non-cash adjustments	(16,000)	84,000
Changes in operating assets and liabilities:
Accounts receivable	2,355,000	2,566,000
Inventories	(131,000)	(526,000)
Prepaid expenses and other assets	0	760,000
Accounts payable	(1,043,000)	(1,361,000)
Accrued compensation	(2,475,000)	(992,000)
Other current and non-current liabilities	(126,000)	(321,000)
Net cash used in operating activities	(8,181,000)	(6,052,000)
Investing activities:
Purchases of property and equipment, net	(333,000)	(465,000)
Purchases of marketable securities	(12,014,000)	(7,900,000)
Maturities of marketable securities	7,800,000	18,000,000
Net cash provided by (used in) investing activities	(4,547,000)	9,635,000
Financing activities:
Principal repayment of borrowings	(35,116,000)	(22,000)
Proceeds from borrowings	50,000,000	0
Payments associated with debt issuance	(3,588,000)	(20,000)
Proceeds from stock option exercises	(430,000)	(17,000)
Net cash provided by financing activities	11,726,000	(25,000)
Effect of exchange rate changes on cash, cash equivalents, and restricted cash	20,000	(34,000)
Net increase (decrease) in cash, cash equivalents, and restricted cash	(982,000)	3,524,000
Cash, cash equivalents, and restricted cash at beginning of year	37,044,000	27,512,000
Cash, cash equivalents, and restricted cash at end of period	36,062,000	31,036,000
Non-cash investing and financing activities:
Transfer of systems (from) to property and equipment into (from) inventory	351,000	569,000
Property and equipment included in accounts payable	36,000	147,000
Supplemental cash flow information:
Cash paid for income taxes, net	44,000	33,000
Cash paid for interest	$ 761,000	$ 508,000

Statement of Stockholders' Equi

Statement of Stockholders' Equity Statement - USD ($) shares in Thousands	Total	Additional Paid-in Capital [Member]	Common Stock [Member]	AOCI Attributable to Parent [Member]	Retained Earnings [Member]
Shares, Outstanding			55,066
Stockholders' Equity Attributable to Parent	$ 71,154,000	$ 487,525,000	$ 6,000	$ 8,000	$ (416,385,000)
Stock-based compensation	2,724,000
Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition	2,724,000	2,724,000	$ 0	0	0
Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures	0
Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures			4
Stock Issued During Period, Value, Share-based Compensation, Net of Forfeitures	17,000	17,000
Net Income (Loss) Attributable to Parent	(11,423,000)				(11,423,000)
Temporary Equity, Foreign Currency Translation Adjustments	34,000			34,000
Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures			342
Adjustments to Additional Paid in Capital, Stock Issued, Issuance Costs	40,000	40,000
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax	8,000			8,000
Shares, Outstanding			55,412
Stockholders' Equity Attributable to Parent	62,554,000	490,306,000	$ 6,000	50,000	(427,808,000)
Shares, Outstanding			56,240
Stockholders' Equity Attributable to Parent	33,547,000	500,344,000	$ 6,000	80,000	(466,883,000)
Stock-based compensation	2,544,000
Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition	2,544,000	2,544,000
Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures			$ 715,000
Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures			71
Stock Issued During Period, Value, Share-based Compensation, Net of Forfeitures	430,000	430,000
Net Income (Loss) Attributable to Parent	(12,080,000)				(12,080,000)
Temporary Equity, Foreign Currency Translation Adjustments	(6,000)			(6,000)
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax, Portion Attributable to Parent	2,000			2,000
Shares, Outstanding			57,026
Stockholders' Equity Attributable to Parent	$ 24,437,000	$ 503,318,000	$ 6,000	$ 76,000	$ (478,963,000)

Organization and Basis of Prese

Organization and Basis of Presentation (Notes)	3 Months Ended
	Mar. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Basis of Presentation	Organization and Basis of Presentation GenMark Diagnostics, Inc., the Company or GenMark, was formed by Osmetech plc as a Delaware corporation in February 2010, and had no operations prior to its initial public offering, which was completed in June 2010. The Company is a provider of multiplex molecular diagnostic solutions designed to enhance patient care, improve key quality metrics, and reduce the total cost-of-care. Basis of Presentation and Principles of Consolidation The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with United States generally accepted accounting principles, or U.S. GAAP, and applicable regulations of the U.S. Securities and Exchange Commission, or the SEC, and should be read in conjunction with the audited financial statements included in the Company's Annual Report on Form 10-K for the fiscal year ended December 31, 2018 filed with the SEC on February 25, 2019. These unaudited condensed consolidated financial statements reflect all adjustments that are, in the opinion of management, necessary for a fair statement of the results for the interim periods presented. These adjustments are of a normal, recurring nature. Interim period operating results may not be indicative of the operating results for the full year or any future period. The unaudited condensed consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation. The Company has experienced net losses and negative cash flows from operating activities since its inception and had an accumulated deficit of $478,963,000 as of March 31, 2019 . The Company's ability to transition to profitable operations is dependent upon achieving a level of revenues adequate to support its cost structure through expanding its product offerings and consequently increasing its product revenues. As of March 31, 2019 , the Company had available cash, cash equivalents, and marketable securities of $48,422,000 and working capital of $51,896,000 available to fund future operations. The Company has prepared cash flow forecasts which indicate, based on the Company's current cash resources available and working capital, that the Company will have sufficient resources to fund its operations for at least one year after the date the financial statements are issued. Use of Estimates The preparation of consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the amounts reported in the financial statements and the notes thereto. The Company’s significant estimates included in the preparation of the financial statements are related to accounts receivable, inventories, property and equipment, leases, intangible assets, employee-related compensation accruals, warranty liabilities, tax valuation accounts, and stock-based compensation. Actual results could differ from those estimates. Segment Information The Company currently operates in one reportable business segment, which encompasses the development, manufacturing, sales and support of instruments and molecular tests based on its proprietary eSensor® detection technology. Substantially all of the Company’s operations and assets are in the United States. Recent Accounting Pronouncements From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board, or the FASB, or other standard setting bodies that the Company adopts as of the specified effective date. In June 2018, the FASB issued Accounting Standards Update, or ASU 2018-07, Compensation - Stock Compensation (Topic 718) , which simplifies the accounting for non-employee share-based payment transactions. The new standard expands the scope of Topic 718 to include share-based payment transactions for acquiring goods and services from non-employees. ASU 2018-07 is effective for fiscal years beginning after December 15, 2018 (including interim periods within that fiscal year), with early adoption permitted. The Company adopted this new standard in the second quarter of 2018 and determined its application did not have a material impact on the Company's unaudited condensed consolidated financial statements. In February 2016, the FASB issued ASU 2016-02, Leases, which outlines a comprehensive lease accounting model and supersedes the current lease guidance. The new guidance requires lessees to recognize lease liabilities and corresponding right-of-use, or ROU, assets for all leases with lease terms of greater than 12 months. The guidance also changes the definition of a lease and expands the disclosure requirements of lease arrangements. The new guidance must be adopted using the modified retrospective approach and is effective for annual periods beginning after December 15, 2018. The Company adopted the new standard in the first quarter of 2019 using the package of transition practical expedients. The Company recognized current and non-current ROU assets of $1,261,000 and $3,836,000, respectively, and current and non-current lease liabilities of $1,780,000 and $6,832,000 upon adoption. Deferred rent is now presented as an offset to the Company's current and non-current operating lease ROU assets. The new lease standard did not have a material impact on the Company's unaudited condensed consolidated statements of operations, cash flows, or stockholders' equity. Revenue The Company recognizes revenue from operations through the sale of products and other services. Product revenue comprises the sale of diagnostic tests and instruments. Revenue is recognized when control of products and services is transferred to the customer in an amount that reflects the consideration that the Company expects to receive from the customer in exchange for those products and services. This process involves identifying the contract with the customer, determining the performance obligations in the contract, determining the contract price, allocating the contract price to the distinct performance obligations in the contract, and recognizing revenue when the performance obligations have been satisfied. A performance obligation is considered distinct from other obligations in a contract when it provides a benefit to the customer either on its own or together with other resources that are readily available to the customer and is separately identified in the contract. The Company considers a performance obligation satisfied once it has transferred control of a good or service to the customer, meaning the customer has the ability to use and obtain the benefit of the good or service. The Company recognizes revenue for satisfied performance obligations only when it determines there are no uncertainties regarding payment terms or transfer of control. Revenue from product sales is recognized generally upon shipment to the end customer, which is when control of the product is deemed to be transferred. Invoicing typically occurs upon shipment and the term between invoicing and when payment is due is not significant. Revenue from instrument services is recognized as the services are rendered, typically evenly over the contract term. Revenue is recorded net of discounts and sales taxes collected on behalf of governmental authorities. Employee sales commissions are recorded as selling, general and administrative expenses when incurred or amortized over the estimated contract term when resulting from new contract acquisition efforts. The Company allocates contract price to each performance obligation in proportion to its stand-alone selling price. The stand-alone selling price is determined by the Company's best estimate of stand-alone selling price using average selling prices over a rolling 12-month period along with a specific assessment of any unique circumstances of the contract. For those products for which there is limited sales history, the Company makes price determination based on similar product sales data. The following table represents disaggregated revenue by source (in thousands): Three Months Ended March 31, 2019 2018 Revenue Source: ePlex product revenue $ 15,651 $ 11,922 XT-8 product revenue 5,720 8,654 Total product revenue 21,371 20,576 License and other revenue 162 69 Total revenue $ 21,533 $ 20,645 Cash, Cash Equivalents and Marketable Securities Cash and cash equivalents consist of cash on deposit with banks, money market instruments and certificates of deposit with original maturities of three months or less at the date of purchase. Marketable securities consist of certificates of deposits that mature in greater than three months. Marketable securities are accounted for as "available-for-sale" with the carrying amounts reported in the balance sheets stated at cost, which approximates their fair market value, with unrealized gains and losses, if any, reported as a separate component of stockholders' equity and included in comprehensive loss. Restricted Cash Restricted cash represents amounts designated for uses other than current operations and comprised $758,000 as of both March 31, 2019 and December 31, 2018 , held as security for the Company’s letter of credit with Banc of California. Receivables Accounts receivable consist of amounts due to the Company for sales to customers and are recorded net of an allowance for doubtful accounts. The allowance for doubtful accounts is determined based on an assessment of the collectability of specific customer accounts, the aging of accounts receivable, and a reserve for unknown items based upon the Company’s historical experience. Product Warranties The Company generally offers a one year warranty for its instruments sold to customers and typically up to a sixty day warranty for consumables. Factors that affect the Company’s warranty reserves include the number of units sold, historical and anticipated rates of warranty repairs, and the cost per repair. The Company periodically assesses the adequacy of its warranty reserve and adjusts the amount as appropriate. Intangible Assets Intangible assets comprise licenses or sublicenses to technology covered by patents owned by third parties, and are amortized on a straight-line basis over the expected useful lives of these assets, which is generally ten years. Amortization of licenses typically begins upon the Company obtaining access to the licensed technology and is recorded in cost of revenues for licenses supporting commercialized products. The amortization of licenses to technology supporting products in development is recorded in research and development expenses. Impairment of Long-Lived Assets The Company assesses the recoverability of long-lived assets, including intangible assets, by periodically evaluating the carrying value whenever events or changes in circumstances indicate that the carrying amount may not be recoverable. If impairment is indicated, the Company writes down the carrying value of the asset to its estimated fair value. This fair value is primarily determined based on estimated discounted cash flows. Inventories Inventories are stated at the lower of cost (first-in, first-out) or net realizable value and include direct labor, materials, and manufacturing overhead. The Company periodically reviews inventory for evidence of slow-moving or obsolete parts, and writes inventory down to net realizable value, as needed. This write-down is based on management’s review of inventories on hand, compared to estimated future usage and sales, shelf-life assumptions, and assumptions about the likelihood of obsolescence. If actual market conditions are less favorable than those projected by the Company, additional inventory write-downs may be required. Inventory impairment charges establish a new cost basis for inventory and charges are not reversed subsequently to income, even if circumstances later suggest that increased carrying amounts are recoverable. Property and Equipment, net Property, equipment and leasehold improvements are recorded at cost and depreciated using the straight-line method over the estimated useful lives of the assets, which are identified below. Repair and maintenance costs are expensed as incurred. Machinery and laboratory equipment 3 - 5 years Instruments 4 - 5 years Office equipment 3 - 7 years Leasehold improvements over the shorter of the remaining life of the lease or the useful economic life of the asset Leases The Company determines if an arrangement is a lease at inception. Operating leases are included in current and noncurrent operating lease ROU assets and current and noncurrent operating lease liabilities in the consolidated balance sheets. Finance leases are included in other current assets and liabilities and other non-current assets and liabilities in the consolidated balance sheets. ROU assets represent the Company’s right to use an underlying asset over the lease term and lease liabilities represent the Company’s obligation to make lease payments arising from the lease. Operating lease liabilities are recognized at commencement date based on the present value of the Company’s lease payments over the lease term. As most of the Company’s leases do not provide an implicit rate, the Company uses its incremental borrowing rate based on the information available at the commencement date to determine the present value of its lease payments. ROU assets are recognized at the commencement date based upon the initial measurement of the operating lease liability less any lease incentives received. The Company’s lease agreements can include both lease and non-lease components. The Company accounts for each lease component separately from the non-lease components within its lease agreements. Income Taxes Current income tax expense is the amount of income taxes expected to be payable for the current year. A deferred income tax liability or asset is established for the expected future tax consequences resulting from the differences in financial reporting and tax bases of assets and liabilities. A valuation allowance is provided if it is more likely than not that some or all of the deferred tax assets will not be realized. A full valuation allowance has been recorded against the Company’s net deferred tax assets due to the uncertainty surrounding the Company’s ability to utilize these assets in the future. The Company provides for uncertain tax positions when such tax positions do not meet the recognition thresholds or measurement standards prescribed by the authoritative guidance on income taxes. Amounts for uncertain tax positions are adjusted in periods when new information becomes available or when positions are effectively settled. The Company recognizes accrued interest related to uncertain tax positions as a component of income tax expense. A tax position that is more likely than not to be realized is measured at the largest amount of tax benefit that is greater than 50% likely of being realized upon settlement with the taxing authority that has full knowledge of all relevant information. Measurement of a tax position that meets the more likely than not threshold considers the amounts and probabilities of the outcomes that could be realized upon settlement using the facts, circumstances and information available at the reporting date.

Stock-Based Compensation

Stock-Based Compensation	3 Months Ended
	Mar. 31, 2019
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-Based Compensation	Stock-Based Compensation Equity awards may be granted at the discretion of the Compensation Committee of the Board of Directors under the 2010 Plan in connection with the hiring or retention of personnel and are subject to certain conditions. The Company recognizes stock-based compensation expense related to stock options, restricted stock awards, restricted stock units, and market-based stock units granted to employees, directors and non-employee advisors in exchange for services under the Company's 2010 Equity Incentive Plan, or the 2010 Plan, and employee stock purchases under the Company's Amended and Restated 2013 Employee Stock Purchase Plan, or the ESPP. Employee participation in the 2010 Plan is at the discretion of the Compensation Committee of the Board of Directors of the Company. Each equity award grant reduces the number of shares available for grant under the 2010 Plan. Stock-based compensation expense is recorded in cost of sales, sales and marketing, research and development, and/or general and administrative expenses based on the employee's respective function. During the three months ended March 31, 2019 and 2018 , aggregate stock-based compensation expense was $2,544,000 and $2,724,000 , respectively. Stock Options The fair value of stock options granted is derived from the Black-Scholes Option Pricing Model, which uses several judgment-based variables to calculate the expense. The inputs include the expected term of the stock option, the expected volatility and other factors. • Expected Term. Expected term represents the period that the stock-based awards are expected to be outstanding and is determined by using the simplified method. • Expected Volatility . Expected volatility represents the estimated volatility in the Company’s stock price over the expected term of the stock option and is determined by review of the Company’s and similar companies’ historical experience. • Expected Dividend . The Black-Scholes Option Pricing Model calls for a single expected dividend yield as an input. The Company has assumed no dividends as it has never paid dividends and has no current plans to do so. • Risk-Free Interest Rate. The risk-free interest rate used in the Black-Scholes Option Pricing Model is based on published U.S. Treasury rates in effect at the time of grant for periods corresponding with the expected term of the option. All stock options granted under the 2010 Plan are exercisable at a per share price equal to the closing quoted market price of a share of the Company’s common stock on the NASDAQ Global Market on the grant date and generally vest over a period of four years. Stock options are generally exercisable for a period of up to ten years after grant and are typically forfeited if employment is terminated before the options vest. The following table summarizes stock option activity during the three months ended March 31, 2019 : Number of Shares Weighted Average Exercise Price Outstanding at December 31, 2018 2,439,914 $ 9.57 Granted — $ — Exercised (71,833 ) $ 5.98 Cancelled (153,493 ) $ 12.15 Outstanding at March 31, 2019 2,214,588 $ 9.51 Vested and expected to vest at March 31, 2019 2,214,581 $ 9.51 Exercisable at March 31, 2019 2,214,327 $ 9.51 Options that were exercisable as of March 31, 2019 had a remaining weighted average contractual term of 3.77 years, and an aggregate intrinsic value of $1,429,000 . As of March 31, 2019 , there were 2,214,588 stock options outstanding, which had a remaining weighted average contractual term of 3.77 years and an aggregate intrinsic value of $1,429,000 . No stock options were granted during the three months ended March 31, 2019 . Restricted Stock Units Restricted stock units granted under the 2010 Plan generally vest over a period of between one and four years and are typically forfeited if service to the Company ceases before the restricted stock units vest. The compensation expense related to the restricted stock units is calculated as the fair market value of the Company's stock on the grant date and is adjusted for estimated forfeitures. Restrictions expire after the grant date in accordance with specific provisions in the applicable award agreement. The Company’s restricted stock unit activity for the three months ended March 31, 2019 was as follows: Restricted Stock Units Number of Shares Weighted Average Grant Date Fair Value Unvested at December 31, 2018 2,665,708 $ 6.12 Granted 1,352,750 $ 6.70 Vested (569,050 ) $ 5.37 Cancelled (182,539 ) $ 6.55 Unvested at March 31, 2019 3,266,869 $ 6.47 As of March 31, 2019 , there was $15,034,000 of unrecognized compensation cost related to unvested restricted stock units, which is expected to be recognized over a weighted average period of 2.91 years. The total fair value of restricted stock units that vested during the three months ended March 31, 2019 and 2018 was $4,058,000 and $1,523,000 , respectively. Market-Based Stock Units The Company issued market-based stock units in each of February 2019 , 2018 , and 2017 , which may result in the recipient receiving shares of stock equal to 200% of the target number of units granted. The vesting and issuance of Company stock depends on the Company's stock performance as compared to the NASDAQ Composite Index over the three -year period following the grant, subject to the recipient's continued service with the Company. As of March 31, 2019 , there was $3,847,000 of unrecognized stock-based compensation expense related to market-based stock unit awards, which is expected to be recognized over a weighted average period of 2.15 years. The Company’s market-based stock unit activity for the three months ended March 31, 2019 was as follows: Market-Based Stock Units Number of Shares Weighted Average Grant Date Fair Value Unvested at December 31, 2018 328,739 $ 10.03 Units Granted 440,000 $ 10.21 Cancelled (28,334) $ 9.39 Unvested at March 31, 2019 740,405 $ 10.16 The fair value of these market-based stock units was estimated on the grant date using the Monte Carlo Simulation Valuation Model, which estimates the potential outcome of achieving the market condition based on simulated future stock prices, with the following assumptions for the three months ended March 31, 2019 and 2018 : Three Months Ended March 31, 2019 2018 Expected volatility 64 % 65 % Risk-free interest rate 2.50 % 2.40 % Expected dividend — % — % Weighted average fair value $10.11 - $10.31 $ 7.19 Employee Stock Purchase Plan The Company's stockholders approved the ESPP in May 2013. In May 2018, the Company's stockholders approved the amendment and restatement of the ESPP, which increased the shares authorized for issuance under the ESPP from 650,000 shares to 1,750,000 shares. The price at which stock is purchased under the ESPP is equal to 85% of the fair market value of the Company's common stock on the first or the last day of the offering period, whichever is lower. Generally, each offering under the ESPP will be for a period of six months as determined by the Company's Board of Directors; provided that no offering period may exceed 27 months . Employees may invest up to 10% of their qualifying gross compensation through payroll deductions. In no event may an employee purchase more than 1,500 shares of common stock during any six-month offering period. As of March 31, 2019 , there were 940,493 shares of common stock available for issuance under the ESPP. The ESPP is a compensatory plan as defined by the authoritative guidance for stock compensation; therefore, stock-based compensation expense related to the ESPP has been recorded during each of the three months ended March 31, 2019 and 2018 . Stock-Based Compensation Expense Recognition Stock-based compensation was recognized in the unaudited condensed consolidated statements of comprehensive loss as follows (in thousands): Three Months Ended 2019 2018 Cost of revenue $ 204 $ 187 Sales and marketing 619 645 Research and development 423 627 General and administrative 1,298 1,265 Total stock-based compensation expense $ 2,544 $ 2,724 Stock-based compensation capitalized during the periods presented was not material and there was no unrecognized tax benefit related to stock-based compensation for either of the three months ended March 31, 2019 and 2018 .

Net Loss per Common Share (Note

Net Loss per Common Share (Notes)	3 Months Ended
	Mar. 31, 2019
Earnings Per Share [Abstract]
Net Loss per Common Share	Net Loss per Common Share Basic net loss per share is calculated by dividing loss available to stockholders of the Company's common stock (the numerator) by the weighted average number of shares of the Company's common stock outstanding during the period (the denominator). Shares issued during the period and shares reacquired during the period are weighted for the portion of the period that they were outstanding. Diluted loss per share is calculated in a similar way to basic loss per share except that the denominator is increased to include the number of additional shares that would have been outstanding if the dilutive potential shares had been issued, unless the effect would be anti-dilutive. The calculations of diluted net loss per share for each of the three months ended March 31, 2019 and 2018 did not include the effects of the following stock options and other equity awards which were outstanding as of the end of each period because the inclusion of these securities would have been anti-dilutive (in thousands): Three Months Ended March 31, 2019 2018 Options outstanding to purchase common stock 2,215 2,454 Other unvested equity awards 4,007 3,759 Total 6,222 6,213

Condensed Consolidated Financia

Condensed Consolidated Financial Statement Details (Notes)	3 Months Ended
	Mar. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Condensed Consolidated Financial Statement Details	Condensed Consolidated Financial Statement Details The following tables show the Company's unaudited condensed consolidated financial statement details as of March 31, 2019 and December 31, 2018 (in thousands): Inventory March 31, 2019 December 31, 2018 Raw materials $ 2,344 $ 2,449 Work-in-process 3,131 3,349 Finished goods 3,916 4,446 Total inventories $ 9,391 $ 10,244 Property and Equipment, Net March 31, 2019 December 31, 2018 Property and equipment — at cost: Machinery and laboratory equipment $ 15,013 $ 15,206 Instruments 15,406 15,089 Office equipment 2,135 2,114 Leasehold improvements 10,759 10,648 Total property and equipment — at cost 43,313 43,057 Less: accumulated depreciation (23,386 ) (21,987 ) Property and equipment, net $ 19,927 $ 21,070 Accrued Warranty The following table shows changes in the Company's accrued warranties for each of the three months ended March 31, 2019 and 2018 (in thousands): Three Months Ended March 31, 2019 2018 Beginning accrued warranty balance $ 330 $ 470 Warranty expenses incurred (444 ) (516 ) Provisions 487 464 Ending accrued warranty balance $ 373 $ 418

Intangible Assets, net (Notes)

Intangible Assets, net (Notes)	3 Months Ended
	Mar. 31, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible assets, net	5. Intangible Assets, net Intangible assets as of each of March 31, 2019 and December 31, 2018 comprised the following (in thousands): March 31, 2019 December 31, 2018 Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount Licensed intellectual property $ 4,750 $ (2,875 ) $ 1,875 $ 4,750 $ (2,727 ) $ 2,023 In July 2012, the Company entered into a development collaboration and license agreement with Advanced Liquid Logic, Inc., or ALL, which was acquired by Illumina, Inc. in July 2013. Under the terms of the agreement, the Company established a collaborative program to develop in-vitro diagnostic products incorporating ALL’s proprietary electro-wetting technology in conjunction with the Company’s electrochemical detection technology. Intellectual property licenses have a weighted average remaining amortization period of 3.18 years as of March 31, 2019 . Amortization expense for these licenses was $148,000 and $149,000 for the three months ended March 31, 2019 and 2018 , respectively. Estimated future amortization expense for these licenses is as follows (in thousands): Fiscal Years Ending Future Amortization Expense Remaining in 2019 $ 445 2020 593 2021 593 2022 244 Total $ 1,875

Loan Payable (Notes)

Loan Payable (Notes)	3 Months Ended
	Mar. 31, 2019
Debt Disclosure [Abstract]
Loan payable	Long-term debt As of March 31, 2019 and December 31, 2018 , long-term debt consisted of the following (in thousands): March 31, 2019 December 31, 2018 Term Loans Term Loan A - 6.9% interest $ — $ 7,619 Term Loan B - 6.9% interest — 7,619 Term Loan C - 7.4% interest — 12,000 Term Loan D - 8.8% interest — 663 Term Loan E - 8.8% interest — 7,098 Term Loan - 8.4% interest 50,000 — Final fee obligation 2,975 3,288 Unamortized issuance costs (5,154 ) (2,245 ) Total debt, net 47,821 36,042 Current portion of long-term debt — — Long-term debt $ 47,821 $ 36,042 Term Loans In January 2015, the Company entered into a Loan and Security Agreement, or the LSA, with Solar Capital Partners (as successor-in-interest to General Electric Capital Corporation), and certain other financial institutions party thereto, as lenders. and certain other financial institutions party thereto, as lenders. Pursuant to the LSA and its subsequent amendments, the Company borrowed $42,762,000 in a series of term loans and had the ability to borrow against a revolving loan in the maximum amount of $5,000,000 . During the term of the LSA, the term loans thereunder accrued interest at a rate equal to ( a) the greater of 1.00% or the three year treasury rate in effect at the time of funding, plus (b) an applicable margin between 4.95% and 5.90% per annum. The Company borrowed al l $42,762,000 under the term loans as provided in the LSA, and the Company did not borrow any of the $5,000,000 available under the revolving loan. On February 1, 2019, or the Effective Date, the Company entered into a new Loan and Security Agreement, or the New LSA, with Solar Capital Ltd. and certain other financial institutions, or, collectively, the Lenders. Pursuant to the New LSA, the Lenders are providing the Company with up to $65,000,000 in a series of term loans, or, collectively, the Term Loans, of which $50,000,000 , or the Tranche 1 Loan, was funded on the Effective Date. An additional $15,000,000 , or the Tranche 2 Loan, is available to be funded at the Company's option, but no later than December 31, 2019 , provided that the Company achieves a designated amount of product revenues on a trailing six-month basis. On the Effective Date, approximately $38,800,000 of the proceeds from the Tranche 1 Loan were used by the Company to repay all outstanding principal, interest, related fees, and other obligations under the LSA, with the remaining borrowings to be used to satisfy the Company's working capital needs and for other general business purposes. The Company accounted for the repayment of its obligations under the LSA as a debt modification. The Company has capitalized the issuance costs it incurred when entering into the New LSA, which are being amortized over the remaining term of the New LSA. The Term Loans will accrue interest at a floating per annum rate in effect from time-to-time equal to (a) the greater of 2.51% or the one-month LIBOR rate then in effect as of the applicable payment date, plus (b) 5.90% per annum . The Company is only required to make interest payments on amounts borrowed pursuant to the Term Loans from the applicable funding date until February 28, 2021 , or the Interest Only Period. If the Company exercises its option to borrow the Tranche 2 Loan and the Company achieves an additional designated amount of product revenues on a trailing six-month basis on or before December 31, 2020 , then the Interest Only Period may, at the Company’s election, be extended for both Term Loans through February 28, 2022 . Following the Interest Only Period (as the same may be extended pursuant to the terms of the New LSA), monthly installments of principal and interest under the Term Loans will be due until the original principal amount and applicable interest is fully repaid by February 1, 2023 , or the Final Maturity Date. Under the New LSA, the Company is required to comply with certain affirmative and negative covenants, including, without limitation, delivering reports and notices relating to the Company’s financial condition and certain regulatory events and intellectual property matters, as well as limiting the creation of liens, the incurrence of indebtedness, and the making of certain investments, dividends, payments and acquisitions, other than as specifically permitted by the New LSA. As of March 31, 2019 , the Company was in compliance with all covenants under the LSA. The New LSA also contains customary events of default (subject, in certain instances, to specified cure periods), including, but not limited to, the failure to make payments of interest or premium when due, the failure to comply with certain covenants and agreements specified in the New LSA, and the occurrence of a material adverse change, certain regulatory events, or certain insolvency events. Upon the occurrence of an event of default, the Lenders may declare all outstanding principal and accrued but unpaid interest under the New LSA immediately due and payable and may exercise the other rights and remedies as set forth in the New LSA. Debt Issuance Costs As of March 31, 2019 and December 31, 2018 , the Company had $5,154,000 and $2,245,000 , respectively, of unamortized debt issuance discount, which is offset against borrowings in long-term and short-term debt. Amortization of debt issuance costs was $366,000 and $290,000 for the three months ended March 31, 2019 and 2018 , respectively. Amortization of debt issuance costs is included in interest expense in the Company's unaudited condensed consolidated statements of comprehensive loss for the periods presented. Letter of Credit In September 2012, the Company provided a $758,000 letter of credit issued by Banc of California to the landlord of its executive office facility in Carlsbad, California. This letter of credit was secured with $758,000 of restricted cash as of March 31, 2019 .

Leases (Notes)

Leases (Notes)	3 Months Ended
	Mar. 31, 2019
Leases [Abstract]
Leases	Leases The Company has operating and finance lease agreements for its office, manufacturing, warehousing and laboratory space and for office equipment. Rent and operating expenses charged under these arrangements was $526,000 and $427,000 for the three months ended March 31, 2019 and 2018 , respectively. Pursuant to the adoption of the new lease standard, the Company reported current and noncurrent operating lease ROU assets of $1.3 million and $3.7 million , respectively, and current and noncurrent operating lease liabilities of $1.8 million and $6.6 million , respectively, as of March 31, 2019 . The Company reported current and noncurrent deferred rent under the existing lease standard of $520,000 and $2,996,000 , respectively, at December 31, 2018. The Company's operating lease liabilities were measured at a weighted average discount rate of 11.2% and have a weighted average remaining term of 6.55 years. As of March 31, 2019 , the future minimum lease payments required over the next five years under the Company's lease arrangements are as follows (in thousands): Fiscal Years Ending Future Minimum Lease Payments Remaining in 2019 $ 1,504 2020 1,997 2021 2,015 2022 2,077 2023 1,939 Thereafter 2,084 Total $ 11,616

Fair Value of Financial Instrum

Fair Value of Financial Instruments (Notes)	3 Months Ended
	Mar. 31, 2019
Fair Value Disclosures [Abstract]
Fair value of financial instruments	Fair Value of Financial Instruments The carrying amounts of financial instruments, such as cash equivalents, restricted cash, accounts receivable, and accounts payable approximate the related fair values due to the short-term maturities of these instruments. The Company uses a fair value hierarchy with three levels of inputs, of which the first two are considered observable and the last unobservable, to measure fair value: • Level 1 — Quoted prices in active markets for identical assets or liabilities. • Level 2 — Inputs, other than Level 1, that are observable, either directly or indirectly, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. • Level 3 — Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. The following table presents the financial instruments measured at fair value on a recurring basis and the valuation approach applied to each class of financial instruments as of March 31, 2019 and December 31, 2018 (in thousands): March 31, 2019 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total Cash equivalents Money market funds $ 6,004 $ — $ — $ 6,004 Corporate notes and bonds — 1,549 — 1,549 U.S. government and agency securities — 1,999 — 1,999 Commercial paper — 5,285 — 5,285 Marketable securities Corporate notes and bonds — 4,991 — 4,991 U.S. government and agency securities — 6,149 — 6,149 Commercial paper — 1,978 — 1,978 Total $ 6,004 $ 21,951 $ — $ 27,955 December 31, 2018 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total Cash equivalents Money market funds $ 8,953 $ — $ — $ 8,953 Marketable securities Corporate notes and bonds — 6,389 — 6,389 U.S. government and agency securities — 2,493 — 2,493 Total $ 8,953 $ 8,882 $ — $ 17,835 Level 2 marketable securities are priced using quoted market prices for similar instruments or nonbinding market prices that are corroborated by observable market data. The Company uses inputs such as actual trade data, benchmark yields, broker/dealer quotes, and other similar data, which are obtained from quoted market prices, independent pricing vendors, or other sources, to determine the ultimate fair value of these assets and liabilities. The Company uses such pricing data as the primary input to make its assessments and determinations as to the ultimate valuation of its investment portfolio and has not made, during the periods presented, any material adjustments to such inputs.

Marketable Securities (Notes)

Marketable Securities (Notes)	3 Months Ended
	Mar. 31, 2019
Investments, Debt and Equity Securities [Abstract]
Marketable securities	Marketable Securities The following table summarizes the Company’s marketable securities as of each of March 31, 2019 and December 31, 2018 (in thousands): March 31, 2019 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Corporate notes and bonds $ 4,992 $ — $ (1 ) $ 4,991 U.S. government and agency securities 6,149 — — 6,149 Commercial paper 1,979 — (1 ) 1,978 Total $ 13,120 $ — $ (2 ) $ 13,118 December 31, 2018 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Corporate notes and bonds $ 6,393 $ — $ (4 ) $ 6,389 Commercial paper 2,493 — — 2,493 Total $ 8,886 $ — $ (4 ) $ 8,882 All of the Company's marketable securities have a maturity of one year or less.

Income Taxes (Notes)

Income Taxes (Notes)	3 Months Ended
	Mar. 31, 2019
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The Company uses an estimated annual effective tax rate, which is based on expected annual income, statutory tax rates and tax planning opportunities available in the various jurisdictions in which the Company operates, to determine its quarterly provision for income taxes. Certain significant or unusual items are separately recognized in the quarter in which they occur and can be a source of variability in the effective tax rates from quarter to quarter. As of March 31, 2019 , the Company recorded a full valuation allowance against all of its net deferred tax assets due to the uncertainty surrounding the Company’s ability to utilize these assets in the future. Due to the Company's losses, it only records a tax provision or benefit related to uncertain tax positions and related interest and minimum tax payments or refunds. The Company recorded income tax expense of $16,000 and $20,000 for the three months ended March 31, 2019 and 2018 , respectively. The Company is subject to taxation in the United States and in various state and foreign jurisdictions. The Company's federal and state tax returns since inception are subject to examination due to the carryover of net operating losses. As of March 31, 2019 , the Company’s tax years from 2011 through 2012 are subject to examination by the United Kingdom tax authorities related to legacy operations. The statute of limitations for the assessment and collection of income taxes related to other foreign tax returns varies by country. In the foreign countries where we have operations, these time periods generally range from three to five years after the year for which the tax return is due or the tax is assessed.

Organization and Basis of Pre_2

Organization and Basis of Presentation (Policies)	3 Months Ended
	Mar. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation and Principles of Consolidation The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with United States generally accepted accounting principles, or U.S. GAAP, and applicable regulations of the U.S. Securities and Exchange Commission, or the SEC, and should be read in conjunction with the audited financial statements included in the Company's Annual Report on Form 10-K for the fiscal year ended December 31, 2018 filed with the SEC on February 25, 2019. These unaudited condensed consolidated financial statements reflect all adjustments that are, in the opinion of management, necessary for a fair statement of the results for the interim periods presented. These adjustments are of a normal, recurring nature. Interim period operating results may not be indicative of the operating results for the full year or any future period. The unaudited condensed consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation. The Company has experienced net losses and negative cash flows from operating activities since its inception and had an accumulated deficit of $478,963,000 as of March 31, 2019 . The Company's ability to transition to profitable operations is dependent upon achieving a level of revenues adequate to support its cost structure through expanding its product offerings and consequently increasing its product revenues. As of March 31, 2019 , the Company had available cash, cash equivalents, and marketable securities of $48,422,000 and working capital of $51,896,000 available to fund future operations. The Company has prepared cash flow forecasts which indicate, based on the Company's current cash resources available and working capital, that the Company will have sufficient resources to fund its operations for at least one year after the date the financial statements are issued.
Use of Estimates	Use of Estimates The preparation of consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the amounts reported in the financial statements and the notes thereto. The Company’s significant estimates included in the preparation of the financial statements are related to accounts receivable, inventories, property and equipment, leases, intangible assets, employee-related compensation accruals, warranty liabilities, tax valuation accounts, and stock-based compensation. Actual results could differ from those estimates.
Segment Information	Segment Information The Company currently operates in one reportable business segment, which encompasses the development, manufacturing, sales and support of instruments and molecular tests based on its proprietary eSensor® detection technology. Substantially all of the Company’s operations and assets are in the United States.
Recent Accounting Pronouncements	Recent Accounting Pronouncements From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board, or the FASB, or other standard setting bodies that the Company adopts as of the specified effective date. In June 2018, the FASB issued Accounting Standards Update, or ASU 2018-07, Compensation - Stock Compensation (Topic 718) , which simplifies the accounting for non-employee share-based payment transactions. The new standard expands the scope of Topic 718 to include share-based payment transactions for acquiring goods and services from non-employees. ASU 2018-07 is effective for fiscal years beginning after December 15, 2018 (including interim periods within that fiscal year), with early adoption permitted. The Company adopted this new standard in the second quarter of 2018 and determined its application did not have a material impact on the Company's unaudited condensed consolidated financial statements. In February 2016, the FASB issued ASU 2016-02, Leases, which outlines a comprehensive lease accounting model and supersedes the current lease guidance. The new guidance requires lessees to recognize lease liabilities and corresponding right-of-use, or ROU, assets for all leases with lease terms of greater than 12 months. The guidance also changes the definition of a lease and expands the disclosure requirements of lease arrangements. The new guidance must be adopted using the modified retrospective approach and is effective for annual periods beginning after December 15, 2018. The Company adopted the new standard in the first quarter of 2019 using the package of transition practical expedients. The Company recognized current and non-current ROU assets of $1,261,000 and $3,836,000, respectively, and current and non-current lease liabilities of $1,780,000 and $6,832,000 upon adoption. Deferred rent is now presented as an offset to the Company's current and non-current operating lease ROU assets. The new lease standard did not have a material impact on the Company's unaudited condensed consolidated statements of operations, cash flows, or stockholders' equity.
Revenue from Contract with Customer	Revenue The Company recognizes revenue from operations through the sale of products and other services. Product revenue comprises the sale of diagnostic tests and instruments. Revenue is recognized when control of products and services is transferred to the customer in an amount that reflects the consideration that the Company expects to receive from the customer in exchange for those products and services. This process involves identifying the contract with the customer, determining the performance obligations in the contract, determining the contract price, allocating the contract price to the distinct performance obligations in the contract, and recognizing revenue when the performance obligations have been satisfied. A performance obligation is considered distinct from other obligations in a contract when it provides a benefit to the customer either on its own or together with other resources that are readily available to the customer and is separately identified in the contract. The Company considers a performance obligation satisfied once it has transferred control of a good or service to the customer, meaning the customer has the ability to use and obtain the benefit of the good or service. The Company recognizes revenue for satisfied performance obligations only when it determines there are no uncertainties regarding payment terms or transfer of control. Revenue from product sales is recognized generally upon shipment to the end customer, which is when control of the product is deemed to be transferred. Invoicing typically occurs upon shipment and the term between invoicing and when payment is due is not significant. Revenue from instrument services is recognized as the services are rendered, typically evenly over the contract term. Revenue is recorded net of discounts and sales taxes collected on behalf of governmental authorities. Employee sales commissions are recorded as selling, general and administrative expenses when incurred or amortized over the estimated contract term when resulting from new contract acquisition efforts. The Company allocates contract price to each performance obligation in proportion to its stand-alone selling price. The stand-alone selling price is determined by the Company's best estimate of stand-alone selling price using average selling prices over a rolling 12-month period along with a specific assessment of any unique circumstances of the contract. For those products for which there is limited sales history, the Company makes price determination based on similar product sales data. The following table represents disaggregated revenue by source (in thousands): Three Months Ended March 31, 2019 2018 Revenue Source: ePlex product revenue $ 15,651 $ 11,922 XT-8 product revenue 5,720 8,654 Total product revenue 21,371 20,576 License and other revenue 162 69 Total revenue $ 21,533 $ 20,645
Cash, Cash Equivalents and Marketable Securities	Cash, Cash Equivalents and Marketable Securities Cash and cash equivalents consist of cash on deposit with banks, money market instruments and certificates of deposit with original maturities of three months or less at the date of purchase. Marketable securities consist of certificates of deposits that mature in greater than three months. Marketable securities are accounted for as "available-for-sale" with the carrying amounts reported in the balance sheets stated at cost, which approximates their fair market value, with unrealized gains and losses, if any, reported as a separate component of stockholders' equity and included in comprehensive loss.
Receivables	Receivables Accounts receivable consist of amounts due to the Company for sales to customers and are recorded net of an allowance for doubtful accounts. The allowance for doubtful accounts is determined based on an assessment of the collectability of specific customer accounts, the aging of accounts receivable, and a reserve for unknown items based upon the Company’s historical experience.
Product Warranties	Product Warranties The Company generally offers a one year warranty for its instruments sold to customers and typically up to a sixty day warranty for consumables. Factors that affect the Company’s warranty reserves include the number of units sold, historical and anticipated rates of warranty repairs, and the cost per repair. The Company periodically assesses the adequacy of its warranty reserve and adjusts the amount as appropriate.
Intangible Assets	Intangible Assets Intangible assets comprise licenses or sublicenses to technology covered by patents owned by third parties, and are amortized on a straight-line basis over the expected useful lives of these assets, which is generally ten years. Amortization of licenses typically begins upon the Company obtaining access to the licensed technology and is recorded in cost of revenues for licenses supporting commercialized products. The amortization of licenses to technology supporting products in development is recorded in research and development expenses.
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets The Company assesses the recoverability of long-lived assets, including intangible assets, by periodically evaluating the carrying value whenever events or changes in circumstances indicate that the carrying amount may not be recoverable. If impairment is indicated, the Company writes down the carrying value of the asset to its estimated fair value. This fair value is primarily determined based on estimated discounted cash flows.
Inventories	Inventories Inventories are stated at the lower of cost (first-in, first-out) or net realizable value and include direct labor, materials, and manufacturing overhead. The Company periodically reviews inventory for evidence of slow-moving or obsolete parts, and writes inventory down to net realizable value, as needed. This write-down is based on management’s review of inventories on hand, compared to estimated future usage and sales, shelf-life assumptions, and assumptions about the likelihood of obsolescence. If actual market conditions are less favorable than those projected by the Company, additional inventory write-downs may be required. Inventory impairment charges establish a new cost basis for inventory and charges are not reversed subsequently to income, even if circumstances later suggest that increased carrying amounts are recoverable.
Property and Equipment, net	Property and Equipment, net Property, equipment and leasehold improvements are recorded at cost and depreciated using the straight-line method over the estimated useful lives of the assets, which are identified below. Repair and maintenance costs are expensed as incurred. Machinery and laboratory equipment 3 - 5 years Instruments 4 - 5 years Office equipment 3 - 7 years Leasehold improvements over the shorter of the remaining life of the lease or the useful economic life of the asset
Income Taxes	Income Taxes Current income tax expense is the amount of income taxes expected to be payable for the current year. A deferred income tax liability or asset is established for the expected future tax consequences resulting from the differences in financial reporting and tax bases of assets and liabilities. A valuation allowance is provided if it is more likely than not that some or all of the deferred tax assets will not be realized. A full valuation allowance has been recorded against the Company’s net deferred tax assets due to the uncertainty surrounding the Company’s ability to utilize these assets in the future. The Company provides for uncertain tax positions when such tax positions do not meet the recognition thresholds or measurement standards prescribed by the authoritative guidance on income taxes. Amounts for uncertain tax positions are adjusted in periods when new information becomes available or when positions are effectively settled. The Company recognizes accrued interest related to uncertain tax positions as a component of income tax expense. A tax position that is more likely than not to be realized is measured at the largest amount of tax benefit that is greater than 50% likely of being realized upon settlement with the taxing authority that has full knowledge of all relevant information. Measurement of a tax position that meets the more likely than not threshold considers the amounts and probabilities of the outcomes that could be realized upon settlement using the facts, circumstances and information available at the reporting date.

Organization and Basis of Pre_3

Organization and Basis of Presentation (Tables)	3 Months Ended
	Mar. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Disaggregation of Revenue	The following table represents disaggregated revenue by source (in thousands): Three Months Ended March 31, 2019 2018 Revenue Source: ePlex product revenue $ 15,651 $ 11,922 XT-8 product revenue 5,720 8,654 Total product revenue 21,371 20,576 License and other revenue 162 69 Total revenue $ 21,533 $ 20,645
Property, Plant and Equipment	Property, equipment and leasehold improvements are recorded at cost and depreciated using the straight-line method over the estimated useful lives of the assets, which are identified below. Repair and maintenance costs are expensed as incurred. Machinery and laboratory equipment 3 - 5 years Instruments 4 - 5 years Office equipment 3 - 7 years Leasehold improvements over the shorter of the remaining life of the lease or the useful economic life of the asset Property and Equipment, Net March 31, 2019 December 31, 2018 Property and equipment — at cost: Machinery and laboratory equipment $ 15,013 $ 15,206 Instruments 15,406 15,089 Office equipment 2,135 2,114 Leasehold improvements 10,759 10,648 Total property and equipment — at cost 43,313 43,057 Less: accumulated depreciation (23,386 ) (21,987 ) Property and equipment, net $ 19,927 $ 21,070

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2019
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Schedule of share-based compensation, stock options, activity	The following table summarizes stock option activity during the three months ended March 31, 2019 : Number of Shares Weighted Average Exercise Price Outstanding at December 31, 2018 2,439,914 $ 9.57 Granted — $ — Exercised (71,833 ) $ 5.98 Cancelled (153,493 ) $ 12.15 Outstanding at March 31, 2019 2,214,588 $ 9.51 Vested and expected to vest at March 31, 2019 2,214,581 $ 9.51 Exercisable at March 31, 2019 2,214,327 $ 9.51
Schedule of share-based compensation, restricted stock units, activity	The Company’s restricted stock unit activity for the three months ended March 31, 2019 was as follows: Restricted Stock Units Number of Shares Weighted Average Grant Date Fair Value Unvested at December 31, 2018 2,665,708 $ 6.12 Granted 1,352,750 $ 6.70 Vested (569,050 ) $ 5.37 Cancelled (182,539 ) $ 6.55 Unvested at March 31, 2019 3,266,869 $ 6.47
Schedule of share-based compensation, market based stock units, activity	The Company’s market-based stock unit activity for the three months ended March 31, 2019 was as follows: Market-Based Stock Units Number of Shares Weighted Average Grant Date Fair Value Unvested at December 31, 2018 328,739 $ 10.03 Units Granted 440,000 $ 10.21 Cancelled (28,334) $ 9.39 Unvested at March 31, 2019 740,405 $ 10.16
Schedule of share-based compensation, market based stock units, valuation assumptions	The fair value of these market-based stock units was estimated on the grant date using the Monte Carlo Simulation Valuation Model, which estimates the potential outcome of achieving the market condition based on simulated future stock prices, with the following assumptions for the three months ended March 31, 2019 and 2018 : Three Months Ended March 31, 2019 2018 Expected volatility 64 % 65 % Risk-free interest rate 2.50 % 2.40 % Expected dividend — % — % Weighted average fair value $10.11 - $10.31 $ 7.19
Schedule of employee service share-based compensation, allocation of recognized period costs	Stock-based compensation was recognized in the unaudited condensed consolidated statements of comprehensive loss as follows (in thousands): Three Months Ended 2019 2018 Cost of revenue $ 204 $ 187 Sales and marketing 619 645 Research and development 423 627 General and administrative 1,298 1,265 Total stock-based compensation expense $ 2,544 $ 2,724

Net Loss per Common Share (Tabl

Net Loss per Common Share (Tables)	3 Months Ended
	Mar. 31, 2019
Earnings Per Share [Abstract]
Computations of diluted net loss per share	The calculations of diluted net loss per share for each of the three months ended March 31, 2019 and 2018 did not include the effects of the following stock options and other equity awards which were outstanding as of the end of each period because the inclusion of these securities would have been anti-dilutive (in thousands): Three Months Ended March 31, 2019 2018 Options outstanding to purchase common stock 2,215 2,454 Other unvested equity awards 4,007 3,759 Total 6,222 6,213

Condensed Consolidated Financ_2

Condensed Consolidated Financial Statement Details (Tables)	3 Months Ended
	Mar. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Inventories	Inventory March 31, 2019 December 31, 2018 Raw materials $ 2,344 $ 2,449 Work-in-process 3,131 3,349 Finished goods 3,916 4,446 Total inventories $ 9,391 $ 10,244
Property and equipment, net	Property, equipment and leasehold improvements are recorded at cost and depreciated using the straight-line method over the estimated useful lives of the assets, which are identified below. Repair and maintenance costs are expensed as incurred. Machinery and laboratory equipment 3 - 5 years Instruments 4 - 5 years Office equipment 3 - 7 years Leasehold improvements over the shorter of the remaining life of the lease or the useful economic life of the asset Property and Equipment, Net March 31, 2019 December 31, 2018 Property and equipment — at cost: Machinery and laboratory equipment $ 15,013 $ 15,206 Instruments 15,406 15,089 Office equipment 2,135 2,114 Leasehold improvements 10,759 10,648 Total property and equipment — at cost 43,313 43,057 Less: accumulated depreciation (23,386 ) (21,987 ) Property and equipment, net $ 19,927 $ 21,070
Accrued warranty	Accrued Warranty The following table shows changes in the Company's accrued warranties for each of the three months ended March 31, 2019 and 2018 (in thousands): Three Months Ended March 31, 2019 2018 Beginning accrued warranty balance $ 330 $ 470 Warranty expenses incurred (444 ) (516 ) Provisions 487 464 Ending accrued warranty balance $ 373 $ 418

Intangible Assets, net (Tables)

Intangible Assets, net (Tables)	3 Months Ended
	Mar. 31, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Summary of intangible assets	Intangible assets as of each of March 31, 2019 and December 31, 2018 comprised the following (in thousands): March 31, 2019 December 31, 2018 Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount Licensed intellectual property $ 4,750 $ (2,875 ) $ 1,875 $ 4,750 $ (2,727 ) $ 2,023
Summary of estimated future amortization expense	Estimated future amortization expense for these licenses is as follows (in thousands): Fiscal Years Ending Future Amortization Expense Remaining in 2019 $ 445 2020 593 2021 593 2022 244 Total $ 1,875

Loan Payable (Tables)

Loan Payable (Tables)	3 Months Ended
	Mar. 31, 2019
Debt Disclosure [Abstract]
Schedule of long-term debt instruments	As of March 31, 2019 and December 31, 2018 , long-term debt consisted of the following (in thousands): March 31, 2019 December 31, 2018 Term Loans Term Loan A - 6.9% interest $ — $ 7,619 Term Loan B - 6.9% interest — 7,619 Term Loan C - 7.4% interest — 12,000 Term Loan D - 8.8% interest — 663 Term Loan E - 8.8% interest — 7,098 Term Loan - 8.4% interest 50,000 — Final fee obligation 2,975 3,288 Unamortized issuance costs (5,154 ) (2,245 ) Total debt, net 47,821 36,042 Current portion of long-term debt — — Long-term debt $ 47,821 $ 36,042

Leases (Tables)

Leases (Tables)	3 Months Ended
	Mar. 31, 2019
Leases [Abstract]
Schedule of future minimum lease payments	As of March 31, 2019 , the future minimum lease payments required over the next five years under the Company's lease arrangements are as follows (in thousands): Fiscal Years Ending Future Minimum Lease Payments Remaining in 2019 $ 1,504 2020 1,997 2021 2,015 2022 2,077 2023 1,939 Thereafter 2,084 Total $ 11,616

Fair Value of Financial Instr_2

Fair Value of Financial Instruments (Tables)	3 Months Ended
	Mar. 31, 2019
Fair Value Disclosures [Abstract]
Assets measured at fair value on a recurring basis	The following table presents the financial instruments measured at fair value on a recurring basis and the valuation approach applied to each class of financial instruments as of March 31, 2019 and December 31, 2018 (in thousands): March 31, 2019 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total Cash equivalents Money market funds $ 6,004 $ — $ — $ 6,004 Corporate notes and bonds — 1,549 — 1,549 U.S. government and agency securities — 1,999 — 1,999 Commercial paper — 5,285 — 5,285 Marketable securities Corporate notes and bonds — 4,991 — 4,991 U.S. government and agency securities — 6,149 — 6,149 Commercial paper — 1,978 — 1,978 Total $ 6,004 $ 21,951 $ — $ 27,955 December 31, 2018 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total Cash equivalents Money market funds $ 8,953 $ — $ — $ 8,953 Marketable securities Corporate notes and bonds — 6,389 — 6,389 U.S. government and agency securities — 2,493 — 2,493 Total $ 8,953 $ 8,882 $ — $ 17,835

Marketable Securities (Tables)

Marketable Securities (Tables)	3 Months Ended
	Mar. 31, 2019
Investments, Debt and Equity Securities [Abstract]
Marketable securities, gross unrealized gains/losses	March 31, 2019 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Corporate notes and bonds $ 4,992 $ — $ (1 ) $ 4,991 U.S. government and agency securities 6,149 — — 6,149 Commercial paper 1,979 — (1 ) 1,978 Total $ 13,120 $ — $ (2 ) $ 13,118 December 31, 2018 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Corporate notes and bonds $ 6,393 $ — $ (4 ) $ 6,389 Commercial paper 2,493 — — 2,493 Total $ 8,886 $ — $ (4 ) $ 8,882

Organization and Basis of Pre_4

Organization and Basis of Presentation - Revenue disaggregation (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Disaggregation of Revenue
Product revenue	$ 21,371	$ 20,576
License and other revenue	162	69
Total revenue	21,533	20,645
ePlex Revenue
Disaggregation of Revenue
Product revenue	15,651	11,922
XT-8 Revenue
Disaggregation of Revenue
Product revenue	$ 5,720	$ 8,654

Organization and Basis of Pre_5

Organization and Basis of Presentation - Property and equipment (Details)	3 Months Ended
	Mar. 31, 2019
Property and Equipment
Finite-Lived Intangible Asset, Useful Life	10 years
Machinery and laboratory equipment | Minimum
Property and Equipment
Property, Plant, and Equipment, Useful Life	3 years
Machinery and laboratory equipment | Maximum
Property and Equipment
Property, Plant, and Equipment, Useful Life	5 years
Instruments | Minimum
Property and Equipment
Property, Plant, and Equipment, Useful Life	4 years
Instruments | Maximum
Property and Equipment
Property, Plant, and Equipment, Useful Life	5 years
Office equipment | Minimum
Property and Equipment
Property, Plant, and Equipment, Useful Life	3 years
Office equipment | Maximum
Property and Equipment
Property, Plant, and Equipment, Useful Life	7 years
Leasehold improvements
Property and Equipment
Property, Plant and Equipment, Estimated Useful Lives	over the shorter of the remaining life of the lease or the useful economic life of the asset

Organization and Basis of Pre_6

Organization and Basis of Presentation - Additional information (Details Textual)	3 Months Ended
	Mar. 31, 2019USD ($)Segment	Dec. 31, 2018USD ($)
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Accumulated deficit	$ (478,963,000)	$ (466,883,000)
Cash, cash equivalents, and marketable securities	48,422,000
Working Capital	$ 51,896,000
Sufficient capital to fund its operations	1 year
Number of Reportable Segments | Segment	1
Restricted cash	$ 758,000	$ 758,000
Instruments
Product Warranty Liability
Product warranty period	one year
Reagents
Product Warranty Liability
Product warranty period	sixty day

Stock-Based Compensation - Stoc

Stock-Based Compensation - Stock awards activity (Details) - 2010 Equity Incentive Plan - USD ($)	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Dec. 31, 2018
Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options, outstanding at December 31, 2017, shares	2,439,914
Options, granted, shares	0
Options, exercised, shares	(71,833)
Options, cancelled, shares	(153,493)
Options, outstanding at June 30, 2018, shares	2,214,588
Options, vested and expected to vest, shares	2,214,581
Options, exercisable, shares	2,214,327
Options, outstanding at December 31, 2017, weighted average exercise price	$ 9.51		$ 9.51	$ 9.57
Options, granted, weighted average exercise price	0
Options, exercised, weighted average exercise price	5.98
Options, cancelled, weighted average exercise price	12.15
Options, outstanding at June 30, 2018, weighted average exercise price	9.51
Options, vested and expected to vest, weighted average exercise price	9.51
Options, exercisable, weighted average exercise price	$ 9.51
Options, exercisable, weighted average remaining contractual term	3 years 9 months 7 days
Options, exercisable, intrinsic value			$ 1,429,000
Options, outstanding, weighted average remaining contractual term	3 years 9 months 7 days
Options, outstanding, intrinsic value			1,429,000
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity award other than options, unvested at December 31, 2017, shares	2,665,708
Equity award other than options, granted, shares	1,352,750
Equity award other than options, vested, shares	(569,050)
Equity award other than options, cancelled, shares	(182,539)
Equity award other than options, unvested at June 30, 2018, shares	3,266,869
Equity award other than options, unvested, weighted average grant date fair value	$ 6.12
Equity award other than options, granted, weighted average grant date fair value	6.70
Equity award other than options, vested, weighted average grant date fair value	5.37
Equity award other than options, cancelled, weighted average grant date fair value	6.55
Equity award other than options, unvested, weighted average grant date fair value	$ 6.47
Equity award other than options, vested in period, fair value	$ 4,057,998	$ 1,523,000
Nonvested award, compensation cost not yet recognized			15,034,000
Nonvested award, compensation cost not yet recognized, weighted average period for recognition	2 years 10 months 28 days
Market-based share unit
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity award other than options, unvested at December 31, 2017, shares	328,739
Equity award other than options, granted, shares	440,000
Equity award other than options, cancelled, shares		(28,334)
Equity award other than options, unvested at June 30, 2018, shares	740,405
Equity award other than options, unvested, weighted average grant date fair value	$ 10.03
Equity award other than options, granted, weighted average grant date fair value	10.21	$ 7.19
Equity award other than options, cancelled, weighted average grant date fair value	9.39
Equity award other than options, unvested, weighted average grant date fair value	$ 10.16
Nonvested award, compensation cost not yet recognized			$ 3,847,000
Nonvested award, compensation cost not yet recognized, weighted average period for recognition	2 years 1 month 24 days

Stock-Based Compensation - Valu

Stock-Based Compensation - Valuation assumptions (Details) - 2010 Equity Incentive Plan - Market-based share unit - $ / shares	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value assumptions, expected volatility rate	64.00%	65.00%
Fair value assumptions, risk free interest rate	2.50%	2.40%
Fair value assumptions, expected dividend rate	0.00%	0.00%
Equity award other than options, granted, weighted average grant date fair value	$ 10.21	$ 7.19
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity award other than options, granted, weighted average grant date fair value	10
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity award other than options, granted, weighted average grant date fair value	$ 10

Stock-Based Compensation - Expe

Stock-Based Compensation - Expense recognition (Details) - USD ($)	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation	$ 2,544,000	$ 2,724,000
Allocated share-based compensation expense, capitalized amount	0	0
Allocated share-based compensation expense, tax benefit	0	0
2010 Equity Incentive Plan | Cost of revenue
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Allocated share-based compensation expense	204,000	187,000
2010 Equity Incentive Plan | Sales and marketing
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Allocated share-based compensation expense	619,000	645,000
2010 Equity Incentive Plan | Research and development
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Allocated share-based compensation expense	423,000	627,000
2010 Equity Incentive Plan | General and administrative
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Allocated share-based compensation expense	$ 1,298,000	$ 1,265,000

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional information (Details) - shares	3 Months Ended
	Mar. 31, 2019	May 22, 2013
2010 Equity Incentive Plan | Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	4 years
Award expiration period	10 years
2010 Equity Incentive Plan | Restricted Stock Units (RSUs) | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	1 year
2010 Equity Incentive Plan | Restricted Stock Units (RSUs) | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	4 years
2010 Equity Incentive Plan | Market-based share unit
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum MSU payout percentage	200.00%
Award vesting period	3 years
2013 Employee Stock Purchase Plan | Employee stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized		650,000
Number of shares available for grant	940,493
Discount from market price, offering date	85.00%
Maximum number of shares per employee	1,500
Maximum employee subscription rate	0.00%
2013 Employee Stock Purchase Plan | Employee stock | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Offering period	6 months
2013 Employee Stock Purchase Plan | Employee stock | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Offering period	27 months
2013 Employee Stock Purchase Plan Amended and Restated | Employee stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized	1,750,000

Net Loss per Common Share - Bas

Net Loss per Common Share - Basic and diluted (Details) - shares shares in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Computations of diluted net loss per share
Antidilutive securities excluded from calculation	6,222	6,213
Employee Stock Option
Computations of diluted net loss per share
Antidilutive securities excluded from calculation	2,215	2,454
Other unvested equity awards
Computations of diluted net loss per share
Antidilutive securities excluded from calculation	4,007	3,759

Condensed Consolidated Financ_3

Condensed Consolidated Financial Statement Details - Inventories (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Summary of inventory on hand
Raw materials	$ 2,344	$ 2,449
Work-in-process	3,131	3,349
Finished goods	3,916	4,446
Total	$ 9,391	$ 10,244

Condensed Consolidated Financ_4

Condensed Consolidated Financial Statement Details - Property and equipment, net (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Property and Equipment
Property and equipment — at cost:	$ 43,313	$ 43,057
Less: accumulated depreciation	(23,386)	(21,987)
Property and equipment, net	19,927	21,070
Machinery and laboratory equipment
Property and Equipment
Property and equipment — at cost:	15,013	15,206
Instruments
Property and Equipment
Property and equipment — at cost:	15,406	15,089
Office equipment
Property and Equipment
Property and equipment — at cost:	2,135	2,114
Leasehold improvements
Property and Equipment
Property and equipment — at cost:	$ 10,759	$ 10,648

Condensed Consolidated Financ_5

Condensed Consolidated Financial Statement Details - Accrued warranty (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Product Warranties Disclosures [Abstract]
Beginning accrued warranty balance	$ 330	$ 470
Warranty expenses incurred	(444)	(516)
Provisions	487	464
Ending accrued warranty balance	$ 373	$ 418

Intangible Assets, net - Compon

Intangible Assets, net - Components of gross and net intangible asset balances (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Amortization of intangible assets	$ 148	$ 149
Finite-lived intangible assets
Net carrying amount	$ 1,875
Finite-lived intangible assets, remaining amortization period	3 years 2 months 5 days
Intellectual Property
Finite-lived intangible assets
Gross carrying amount	$ 4,750		$ 4,750
Accumulated amortization	(2,875)		(2,727)
Net carrying amount	$ 1,875		$ 2,023

Intangible Assets, net - Future

Intangible Assets, net - Future amortization expense (Details) $ in Thousands	Mar. 31, 2019USD ($)
Summary of estimated future amortization expense
Remaining in 2018	$ 445
2019	593
2020	593
2021	244
Net carrying amount	$ 1,875

Loan Payable - Term loans and l

Loan Payable - Term loans and line of credit (Details) - USD ($)	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Debt Instrument
Unamortized debt issuance costs	$ (5,154,000)		$ (2,245,000)
Long-term debt, excluding current maturities	47,821,000		36,042,000
Amortization of deferred debt issuance costs	$ 366,000	$ 290,000
Debt instrument, maturity date	Feb. 1, 2023
Debt instrument, interest rate terms	(a) the greater of 2.51% or the one-month LIBOR rate then in effect as of the applicable payment date, plus (b) 5.90% per annum
Long-term Debt, Contingent Payment of Principal or Interest	December 31, 2020
Line of credit facility, maximum borrowing capacity	$ 42,762,000		42,762,000
Term Loans, Debt Facility, Maximum Borrowing Capacity	$ 65,000,000
Tranche 2 Availability Date	Dec. 31, 2019
Proceeds from Issuance of Debt	$ 38,800,000
Restricted cash	758,000		758,000
Letter of credit
Debt Instrument
Letters of credit outstanding, amount	758,000
Revolving credit facility
Debt Instrument
Line of credit facility, maximum borrowing capacity	5,000,000
Line of credit facility, fair value of amount outstanding	0		0
Term Loan A - $10.0 million at 6.9% interest
Debt Instrument
Long-term debt	$ 0		7,619,000
Debt instrument, interest rate, stated percentage	6.90%
Line of credit facility, maximum borrowing capacity	$ 10,000,000		10,000,000
Term Loan B - $10.0 million at 6.9% interest
Debt Instrument
Long-term debt	$ 0		7,619,000
Debt instrument, interest rate, stated percentage	6.90%
Line of credit facility, maximum borrowing capacity	$ 10,000,000		10,000,000
Term Loan C - $15.0 million at 7.4% interest
Debt Instrument
Long-term debt	$ 0		12,000,000
Debt instrument, interest rate, stated percentage	7.40%
Line of credit facility, maximum borrowing capacity	$ 15,000,000		15,000,000
Term Loan D - $0.7 million at 8.8% interest
Debt Instrument
Long-term debt	0		663,000
Final fee obligation	2,975,000		3,288,000
Amortization of deferred debt issuance costs	$ 366,000	$ 290,000
Debt instrument, interest rate terms	a) the greater of 1.00% or the three year treasury rate in effect at the time of funding, plus (b) an applicable margin between 4.95% and 5.90% per annum.
Debt instrument, interest rate, stated percentage	8.80%
Line of credit facility, maximum borrowing capacity	$ 663,455		663,455
Term Loan E [Member]
Debt Instrument
Debt instrument, interest rate, stated percentage	8.80%
Line of credit facility, maximum borrowing capacity	$ 7,098,450		7,098,450
Term Loans [Member]
Debt Instrument
Debt instrument, interest rate, stated percentage	8.40%
Debt Instrument, Face Amount	$ 50,000,000		0
Term Loan E - $7.1 million at 8.8% interest
Debt Instrument
Long-term debt	0		7,098,000
Term Loan - $50 million at 8.4% interest
Debt Instrument
Long-term debt	50,000,000		0
Total debt, net
Debt Instrument
Long-term debt	47,821,000		36,042,000
Long-term debt, current maturities	0		0
Long-term debt, excluding current maturities	$ 47,821,000		$ 36,042,000
Tranche 1 Loan [Member]
Debt Instrument
Debt instrument, interest only period end	Feb. 28, 2021
Term Loans, Debt Facility, Maximum Borrowing Capacity	$ 50,000,000
Tranche 2 Loan [Member]
Debt Instrument
Debt instrument, interest only period end	Feb. 28, 2022
Term Loans, Debt Facility, Maximum Borrowing Capacity	$ 15,000,000

Leases - Future minimum lease p

Leases - Future minimum lease payments (Details) $ in Thousands	Mar. 31, 2019USD ($)
Schedule of future minimum lease payments
Remaining in 2018	$ 1,504
2019	1,997
2020	2,015
2021	2,077
2022	1,939
Thereafter	2,084
Total future minimum payments	$ 11,616

Leases - Additional information

Leases - Additional information (Details) - USD ($)	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Lessee, Lease, Description [Line Items]
Rent and operating expenses	$ 526,000	$ 427,000
Operating Lease, Right-of-Use Asset	1,260,000		$ 0
NoncurrentOperatingLeaseRightOfUseAsset	3,734,000		0
Operating Lease, Liability, Current	1,801,000		0
Operating Lease, Liability, Noncurrent	6,591,000		0
Deferred rent			520,000
Deferred rent	$ 0		$ 2,996,000
Operating Lease, Weighted Average Discount Rate, Percent	11.20%
Operating Lease, Weighted Average Remaining Lease Term	6 years 6 months 18 days

Fair Value of Financial Instr_3

Fair Value of Financial Instruments - Fair value hierarchy (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Fair value, assets measured on a recurring basis
Marketable securities	$ 13,118	$ 8,882
Financial instruments, fair value	27,955	17,835
Level 1
Fair value, assets measured on a recurring basis
Financial instruments, fair value	6,004	8,953
Level 2
Fair value, assets measured on a recurring basis
Financial instruments, fair value	21,951	8,882
Level 3
Fair value, assets measured on a recurring basis
Financial instruments, fair value	0	0
Money market funds
Fair value, assets measured on a recurring basis
Cash equivalents	6,004	8,953
Money market funds | Level 1
Fair value, assets measured on a recurring basis
Cash equivalents	6,004	8,953
Money market funds | Level 2
Fair value, assets measured on a recurring basis
Cash equivalents	0	0
Money market funds | Level 3
Fair value, assets measured on a recurring basis
Cash equivalents	0	0
Corporate notes and bonds
Fair value, assets measured on a recurring basis
Cash equivalents	1,549
Marketable securities	4,991	6,389
Corporate notes and bonds | Level 1
Fair value, assets measured on a recurring basis
Cash equivalents	0
Marketable securities	0	0
Corporate notes and bonds | Level 2
Fair value, assets measured on a recurring basis
Cash equivalents	1,549
Marketable securities	4,991	6,389
Corporate notes and bonds | Level 3
Fair value, assets measured on a recurring basis
Cash equivalents	0
Marketable securities	0	0
U.S. government and agency securities
Fair value, assets measured on a recurring basis
Cash equivalents	1,999
Marketable securities	6,149	2,493
U.S. government and agency securities | Level 1
Fair value, assets measured on a recurring basis
Marketable securities	0	0
U.S. government and agency securities | Level 2
Fair value, assets measured on a recurring basis
Cash equivalents	1,999
Marketable securities	6,149	2,493
U.S. government and agency securities | Level 3
Fair value, assets measured on a recurring basis
Cash equivalents	0
Marketable securities	0	$ 0
Commercial paper
Fair value, assets measured on a recurring basis
Cash equivalents	5,285
Marketable securities	1,978
Commercial paper | Level 1
Fair value, assets measured on a recurring basis
Cash equivalents	0
Marketable securities	0
Commercial paper | Level 2
Fair value, assets measured on a recurring basis
Cash equivalents	5,285
Marketable securities	1,978
Commercial paper | Level 3
Fair value, assets measured on a recurring basis
Cash equivalents	0
Marketable securities	$ 0

Marketable Securities - Gross u

Marketable Securities - Gross unrealized gains/losses (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Marketable securities
Estimated fair value	$ 13,118	$ 8,882
Due in one year or less
Marketable securities
Amortized cost	(13,120)	(8,886)
Gross unrealized gains	0	0
Gross unrealized losses	(2)	(4)
Estimated fair value	13,118	8,882
Corporate notes and bonds
Marketable securities
Estimated fair value	4,991	6,389
Corporate notes and bonds | Due in one year or less
Marketable securities
Amortized cost	(4,992)	(6,393)
Gross unrealized gains	0	0
Gross unrealized losses	(1)	(4)
Estimated fair value	4,991	6,389
U.S. government and agency securities
Marketable securities
Estimated fair value	6,149	2,493
U.S. government and agency securities | Due in one year or less
Marketable securities
Amortized cost	(6,149)
Gross unrealized gains	0
Gross unrealized losses	0
Estimated fair value	6,149
Commercial paper
Marketable securities
Estimated fair value	1,978
Commercial paper | Due in one year or less
Marketable securities
Amortized cost	(1,979)	(2,493)
Gross unrealized gains	0	0
Gross unrealized losses	(1)	0
Estimated fair value	$ 1,978	$ 2,493

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Income Tax Disclosure [Abstract]
Income tax expense (benefit)	$ (16)	$ (20)