GenMark Diagnostics (GNMK) 10-K 25 Feb 21 2020 FY Annual report Financial data

Cover Page

Cover Page - USD ($)	12 Months Ended
	Dec. 31, 2020	Feb. 22, 2021	Jun. 30, 2020
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2020
Document Transition Report	false
Entity File Number	001-34753
Entity Registrant Name	GenMark Diagnostics, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	27-2053069
Entity Address, Address Line One	5964 La Place Court
Entity Address, City or Town	Carlsbad
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	92008
City Area Code	(760)
Local Phone Number	448-4300
Title of 12(b) Security	Common Stock, par value $0.0001 per share
Trading Symbol	GNMK
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Public Float			$ 987,839,000
Entity Common Stock, Shares Outstanding (in shares)		73,085,716
Entity Central Index Key	0001487371
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Amendment Flag	false

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Current assets
Cash and cash equivalents	$ 40,572	$ 44,360
Short-term marketable securities	87,582	9,100
Accounts receivable, net of allowances of $372 and $376, respectively	20,790	16,759
Inventories, net	21,323	11,301
Prepaid expenses and other current assets	2,695	1,877
Total current assets	172,962	83,397
Property and equipment, net	38,362	20,419
Intangible assets, net	841	1,432
Restricted cash	1,646	758
Operating lease, right-of-use asset	8,676	4,642
Other long-term assets	1,047	825
Total assets	223,534	111,473
Current liabilities
Accounts payable	23,071	12,249
Accrued compensation	12,716	7,493
Current operating lease liability	3,093	1,842
Other current liabilities	5,250	2,732
Total current liabilities	44,130	24,316
Long-term debt	71,297	69,145
Noncurrent operating lease liability	12,749	5,796
Other noncurrent liabilities	1,160	53
Total liabilities	129,336	99,310
Stockholders’ equity
Preferred stock, $0.0001 par value; 5,000 authorized, none issued	0	0
Common stock, $0.0001 par value; 100,000 authorized; 71,960 and 60,255 shares issued and outstanding at December 31, 2020 and 2019, respectively	7	6
Additional paid-in capital	626,816	526,294
Accumulated deficit	(532,877)	(514,233)
Accumulated other comprehensive income	252	96
Total stockholders’ equity	94,198	12,163
Total liabilities and stockholders’ equity	$ 223,534	$ 111,473

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Accounts receivable - net of allowance	$ 372	$ 376
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	71,960,000	60,255,000
Common stock, outstanding	71,960,000	60,255,000

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Loss - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Statement [Abstract]
Product revenue	$ 169,148	$ 86,821	$ 69,935
Revenue
Other revenue	2,406	1,200	824
Total revenue	171,554	88,021	70,759
Cost of revenue	103,610	59,418	51,278
Gross profit	67,944	28,603	19,481
Operating expenses
Sales and marketing	23,164	24,118	21,777
General and administrative	25,572	19,159	17,545
Research and development	30,259	27,140	27,931
Total operating expenses	78,995	70,417	67,253
Operating loss	(11,051)	(41,814)	(47,772)
Other income (expense)
Interest income	386	512	711
Interest expense	(7,907)	(5,961)	(3,108)
Other income (expense)	9	(23)	(192)
Total other expense	(7,512)	(5,472)	(2,589)
Loss before income taxes	(18,563)	(47,286)	(50,361)
Income tax expense	81	64	139
Net loss	$ (18,644)	$ (47,350)	$ (50,500)
Net loss per share—basic and diluted	$ (0.28)	$ (0.82)	$ (0.91)
Weighted average number of shares outstanding—basic and diluted	67,541	57,603	55,669
Other comprehensive income
Foreign currency translation adjustments, net of tax	$ 147	$ 11	$ 44
Net unrealized gain on marketable securities, net of tax	9	5	27
Total other comprehensive income	156	16	71
Total comprehensive loss	$ (18,488)	$ (47,334)	$ (50,429)
Revenue from Contract with Customer, Product and Service [Extensible List]	us-gaap:ProductMember

Consolidated Statement of Stock

Consolidated Statement of Stockholders' Equity Statement - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	AOCI Attributable to Parent	Retained Earnings
Beginning balance (in shares) at Dec. 31, 2017		55,066,000
Beginning balance (in usd) at Dec. 31, 2017	$ 71,157	$ 6	$ 487,525	$ 9	$ (416,383)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense	11,697		11,697
Shares issued		253,000
Employee purchases	1,061		1,061
Vesting of restricted stock units		916,000
Shares issued under stock-based compensation plans (in shares)		5,000
Shares issued under stock-based compensation plans (in usd)	21		21
Reimbursement of offering expenses	40		40
Net loss	(50,500)				(50,500)
Foreign currency translation adjustments	44			44
Unrealized gain on marketable securities	27			27
Ending balance (in usd) at Dec. 31, 2018	33,547	$ 6	500,344	80	(466,883)
Ending balance (in shares) at Dec. 31, 2018		56,240,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense	12,046		12,046
Shares issued		210,000
Employee purchases	962		962
Vesting of restricted stock units		1,461,000
Shares issued under stock-based compensation plans (in shares)		81,000
Shares issued under stock-based compensation plans (in usd)	457		457
Issuance of common stock, net of offering costs (in shares)		2,263,000
Issuance of common stock, net of offering costs (in usd)	12,485		12,485
Net loss	(47,350)				(47,350)
Foreign currency translation adjustments	11			11
Unrealized gain on marketable securities	5			5
Ending balance (in usd) at Dec. 31, 2019	12,163	$ 6	526,294	96	(514,233)
Ending balance (in shares) at Dec. 31, 2019		60,255,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense	12,796		12,796
Shares issued		171,000
Employee purchases	1,068		1,068
Vesting of restricted stock units		1,686,000
Shares issued under stock-based compensation plans (in shares)		1,143,000
Shares issued under stock-based compensation plans (in usd)	$ 9,068		9,068
Issuance of common stock, net of offering costs (in shares)	363,120	8,705,000
Issuance of common stock, net of offering costs (in usd)	$ 77,591	$ 1	77,590
Net loss	(18,644)				(18,644)
Foreign currency translation adjustments	147			147
Unrealized gain on marketable securities	9			9
Ending balance (in usd) at Dec. 31, 2020	$ 94,198	$ 7	$ 626,816	$ 252	$ (532,877)
Ending balance (in shares) at Dec. 31, 2020		71,960,000

Consolidated Statement of Cash

Consolidated Statement of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Operating activities
Net loss	$ (18,644)	$ (47,350)	$ (50,500)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities
Depreciation and amortization	7,066	7,268	7,088
Net amortization (accretion) of premiums/discounts on investments	261	(133)	(142)
Amortization of deferred debt issuance costs	2,253	1,740	938
Stock-based compensation	12,796	12,046	11,697
Provision for bad debt, net of recoveries	17	338	23
Non-cash inventory adjustments	2,319	2,631	1,426
Other non-cash adjustments	360	537	15
Changes in operating assets and liabilities
Accounts receivable	(4,105)	(5,584)	(878)
Inventories	(12,478)	(6,534)	(2,414)
Prepaid expenses and other assets	(858)	(750)	854
Accounts payable	5,224	1,501	(1,389)
Accrued compensation	4,945	(885)	1,059
Operating lease right-of-use assets and lease liabilities	4,170	0	0
Other current and non-current liabilities	2,808	249	(289)
Net cash provided by (used in) operating activities	6,134	(34,926)	(32,512)
Investing activities
Purchases of property and equipment	(17,776)	(2,092)	(2,575)
Purchases of marketable securities	(114,186)	(32,135)	(29,778)
Proceeds from sales of marketable securities	1,193	0	0
Maturities of marketable securities	34,260	32,055	66,300
Net cash provided by (used in) investing activities	(96,509)	(2,172)	33,947
Financing activities
Proceeds from issuance of common stock, net of offering costs	78,659	13,447	1,061
Principal repayment of borrowings	(57)	(35,093)	(92)
Proceeds from borrowings	0	70,000	7,098
Payments associated with debt issuance	(100)	(3,638)	(20)
Proceeds from stock option exercises	9,068	457	22
Net cash provided by financing activities	87,570	45,173	8,069
Effect of exchange rate changes on cash, cash equivalents, and restricted cash	(95)	(1)	28
Net increase (decrease) in cash, cash equivalents, and restricted cash	(2,900)	8,074	9,532
Cash, cash equivalents, and restricted cash at beginning of year	45,118	37,044	27,512
Cash, cash equivalents, and restricted cash at end of year	42,218	45,118	37,044
Non-cash investing and financing activities
Transfer of systems to property and equipment from inventory	137	2,846	1,689
Property and equipment included in accounts payable	6,832	1,234	372
Right-of-use assets obtained in exchange for new operating lease liabilities	4,689	0	0
Supplemental cash flow information
Cash paid for interest, net	5,684	3,946	2,028
Cash paid for income taxes, net	$ 91	$ 155	$ 165

Nature of Operations and Summar

Nature of Operations and Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of Operations and Summary of Significant Accounting Policies	1. Nature of Operations and Summary of Significant Accounting Policies Organization GenMark Diagnostics, Inc. (the “Company” or “GenMark”) is a leading provider of multiplex molecular diagnostic solutions designed to enhance patient care, improve key quality metrics, and reduce the total cost-of-care. The Company offers a sample-to-answer ePlex instrument and associated molecular diagnostic panels. The Company’s products also include the XT-8 instrument and related diagnostic and research tests, as well as certain custom manufactured reagents. The Company sells its products directly to customers in the U.S. and primarily via a network of distribution partners internationally. Summary of Significant Accounting Policies Basis of Presentation and Principles of Consolidation The accompanying consolidated financial statements have been prepared in accordance with United States generally accepted accounting principles (“U.S. GAAP”) and applicable regulations of the U.S. Securities and Exchange Commission (“SEC”). These consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation. In June 2020, the Company made a policy election to reclassify freight revenue from product revenue to other revenue. The Company reclassified freight revenue of $0.7 million and $0.5 million for the years ended December 31, 2019 and 2018, respectively, from product revenue to other revenue to conform with the current year presentation. The reclassification had no impact to total revenue for the periods presented. The Company has experienced net losses since its inception and had an accumulated deficit of $532.9 million as of December 31, 2020. 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 December 31, 2020, the Company had available cash, cash equivalents, and marketable securities of $128.2 million and working capital of $128.8 million 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 these 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. 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. Other revenue primarily consists of freight revenue and revenue from extended service agreements. 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 sales and marketing expense 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 determinations based on similar product sales data. The following table represents disaggregated revenue by source ( in thousands ): For the years ended December 31, 2020 2019 2018 Revenue Source ePlex product revenue $ 152,578 $ 59,799 $ 37,601 XT-8 product revenue 16,570 27,022 32,334 Total product revenue 169,148 86,821 69,935 License and other revenue 2,406 1,200 824 Total revenue $ 171,554 $ 88,021 $ 70,759 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. The Company classifies marketable securities as available-for-sale at the time of purchase and reevaluates such classification as of each balance sheet date. All marketable securities are recorded at estimated fair value. Unrealized gains and losses for available-for-sale securities are included in accumulated other comprehensive income, a component of stockholders’ equity. The Company evaluates its marketable securities to assess whether those with unrealized loss positions are other-than-temporarily impaired. Impairments are considered to be other-than-temporary if they are related to deterioration in credit risk or if it is likely that the Company will sell the securities before the recovery of its cost basis. Realized gains and losses and declines in value judged to be other-than-temporary are determined based on the specific identification method and are reported in other income (expense) in the consolidated statements of comprehensive loss. The Company has the ability, if necessary, to liquidate any of its short-term debt securities to meet liquidity needs in the next 12 months. Accordingly, those investments with contractual maturities greater than one year from the date of purchase are classified as short-term investments on the consolidated balance sheets. Restricted Cash Restricted cash represents amounts designated for uses other than current operations and was $1.6 million and $0.8 million at December 31, 2020 and 2019, respectively, which represented an amount held as security for the Company’s facility lease agreements. The following table shows a reconciliation of the Company’s cash and cash equivalents in the consolidated balance sheet to cash, cash equivalents, and restricted cash in the consolidated statement of cash flows as of December 31, 2020 and 2019 ( in thousands ): December 31, 2020 2019 Cash and cash equivalents $ 40,572 $ 44,360 Restricted cash 1,646 758 Total cash, cash equivalents, and restricted cash $ 42,218 $ 45,118 Fair Value of Financial 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 carrying amounts of financial instruments such as accounts receivable, prepaid expenses and other current assets, accounts payable, and accrued liabilities approximate the related fair values due to the short-term maturities of these instruments. Receivables Accounts receivable consists of amounts due to the Company from the sale of products and services to customers. Accounts receivable is recognized at amortized cost and is recorded net of an allowance for credit losses. The Company views its accounts receivable as a single portfolio and considers the period of delinquency, historical collection rates, and customer specific-factors in determining its allowance for credit losses. The following table summarizes the composition of the allowance for credit losses ( in thousands ): For the years ended December 31, 2020 2019 2018 Beginning balance $ 376 $ 75 $ 2,754 Provision for credit losses, net 17 338 23 Write off of uncollectible accounts (21) (37) (2,702) Ending balance $ 372 $ 376 $ 75 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. Product Warranties The Company generally offers a one The following table summarizes warranty reserve activity ( in thousands ): For the years ended December 31, 2020 2019 2018 Beginning balance $ 279 $ 330 $ 470 Provision 1,508 1,275 1,355 Warranty expenses incurred (1,551) (1,326) (1,495) Ending balance $ 236 $ 279 $ 330 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 - 7 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 includes diagnostic instruments used for sales demonstrations or placed with customers under several types of arrangements, including performance evaluation programs (“PEPs”) and reagent rental agreements. Instruments are placed with customers under PEPs for limited evaluation periods. Instruments are also placed with customers under reagent rental agreements, which generally require customers to purchase a minimum number of test cartridges over the term of the agreement. The Company retains title to the instrument under these arrangements. Maintenance and repair costs are expensed as incurred. Leased property meeting certain finance lease criteria is capitalized, and the net present value of the related lease payments is recorded as a liability. Amortization for assets noted as finance leases is recorded using the straight-line method over the shorter of the estimated useful lives or the lease terms. Intangible Assets Intangible assets consist of 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 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. The Company did not recognize any impairment of long-lived asset charges during the years ended December 31, 2020, 2019, and 2018. Other current liabilities The following table summarizes the composition of current liabilities ( in thousands ): December 31, 2020 2019 Accrued royalties $ 1,863 $ 882 Deferred revenue 508 323 Accrued interest 507 437 Accrued warranties 236 279 Other accrued liabilities 2,136 811 Total other current liabilities $ 5,250 $ 2,732 Employee Benefit Plan The Company has a 401(k) tax-deferred savings plan, whereby eligible employees may contribute a percentage of their eligible compensation. The Company makes matching contributions under the 401(k) plan to certain eligible employees. Leases The Company determines if an arrangement is a lease at inception. Operating leases are recorded in the consolidated balance sheets as operating lease right-of-use (“ROU”) assets and current and noncurrent operating lease liabilities. Finance leases are recorded in the consolidated balance sheets as other noncurrent assets and other current and noncurrent liabilities. 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 the 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. Research and Development Costs The Company expenses all research and development costs in the periods in which they are incurred unless there is alternative future use that supports the capitalization of an asset. Stock-Based Compensation The Company recognizes stock-based compensation expense related to stock options, restricted stock units, market-based stock units, and shares purchased under the Company’s Amended and Restated 2013 Employee Stock Purchase Plan (“ESPP”) granted to employees, non-employees, and directors in exchange for services. The compensation expense is based on the fair value of the applicable award utilizing various assumptions regarding the underlying attributes of the award. The stock-based compensation expense is recorded in cost of revenues, sales and marketing, research and development, and/or general and administrative expenses based on the employee’s respective function. The estimated fair value of stock granted, net of forfeitures expected to occur during the vesting period, is amortized as compensation expense that approximates straight-line expense to reflect vesting as it occurs. The compensation expense related to the grant of restricted stock awards or units is calculated as the fair market value of the stock on the grant date as further adjusted to reflect expected forfeitures. The stock option expense is derived from the Black-Scholes option pricing model that uses several judgment-based variables to calculate the expense. The market-based stock expense is derived from the Monte Carlo Simulation Valuation. The inputs utilized in the valuation of the stock-based awards include the following 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 expected volatility in the Company’s stock price over the expected term of the option or market-based award and is determined by review of the Company’s and similar companies’ historical experience. • Expected Dividend— The valuation methods requires a single expected dividend yield as an input. The Company 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 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 or market-based award. Foreign Currency Translation The Company translates the assets and liabilities of the Company’s entities outside the U.S. into U.S. Dollars based on the foreign currency exchange rates at the end of each period. Gains or losses resulting from these foreign currency translations are recorded in accumulated other comprehensive income in the consolidated statement of stockholders’ equity. Foreign currency translation impacts recorded in accumulated other comprehensive income for the years ended December 31, 2020, 2019, and 2018 were $147,000, $11,000, and $44,000, respectively. 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. 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 the years ended December 31, 2020, 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 ): For the years ended December 31, 2020 2019 2018 Options outstanding to purchase common stock 843 2,037 2,440 Other unvested equity awards 3,173 3,124 2,994 Total 4,016 5,161 5,434 Concentration of Risk Financial instruments which potentially subject the Company to concentrations of credit risk consist primarily of cash, cash equivalents, short-term investment securities, and accounts receivable. The Company limits its exposure to credit loss by placing its cash with high credit quality financial institutions. The Company has established guidelines to diversify its cash and investment securities and their maturities that are intended to secure safety and liquidity. For the years ended December 31, 2020, 2019, and 2018, revenue from one customer represented 10%, 14%, and 16%, respectively, of the Company’s total revenue. As of December 31, 2020, no customers accounted for more than 10% of net accounts receivable. As of December 31, 2019, two customers accounted for more than 10% of net accounts receivable, with such customers accounting for 24% and 11% of net accounts receivable. Comprehensive Loss The Company has the option to present the total of comprehensive income, the components of net income, and the components of other comprehensive income either in a single continuous statement of comprehensive income or in two separate but consecutive statements. The Company’s comprehensive loss comprises net loss, unrealized gains and losses on available for sale securities, and foreign currency translation. Recently Adopted Accounting Pronouncements In June 2016, the FASB issued ASU 2016-13, Measurement of Credit Losses on Financial Instruments , which introduced a new methodology for recognizing credit losses on financial instruments. The new standard requires entities to measure financial instruments at their amortized cost basis, net of an allowance for credit losses. The allowance for credit losses must reflect an entity's current estimate of all expected credit losses. The new guidance also requires entities to present credit losses on debt securities accounted for under the available-for-sale method as an allowance rather than a write-down. The Company adopted the new standard in the first quarter of 2020. The adoption of ASU 2016-13 did not have a material impact on the Company’s consolidated financial statements for the year ended December 31, 2020.

Inventories

Inventories	12 Months Ended
	Dec. 31, 2020
Inventory Disclosure [Abstract]
Inventories	2. Inventories The following table summarizes the composition of inventory on hand as of December 31, 2020 and 2019 ( in thousands ): December 31, 2020 2019 Raw materials $ 10,087 $ 3,408 Work-in-process 7,958 3,776 Finished goods 3,278 4,117 Total inventories $ 21,323 $ 11,301

Intangible Assets, Net

Intangible Assets, Net	12 Months Ended
	Dec. 31, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible assets, net	3. Intangible Assets, Net The following table summarizes the composition of intangible assets as of December 31, 2020 and 2019 ( in thousands ): December 31, 2020 December 31, 2019 Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount Licensed intellectual property $ 4,750 $ (3,909) $ 841 $ 4,750 $ (3,318) $ 1,432 Intellectual property licenses have a weighted average remaining amortization period of 1.4 years as of December 31, 2020. Amortization expense for these licenses was $0.6 million during both the years ended December 31, 2020 and 2019. Estimated future amortization expense for these licenses is as follows ( in thousands ): Fiscal Years Ending Future Amortization Expense 2021 $ 591 2022 250 Total $ 841

Property and Equipment, Net

Property and Equipment, Net	12 Months Ended
	Dec. 31, 2020
Property, Plant and Equipment [Abstract]
Property and Equipment, Net	4. Property and Equipment, Net The following table summarizes the composition of property and equipment as of December 31, 2020 and 2019 ( in thousands ) December 31, 2020 December 31, 2019 Property and equipment—at cost: Machinery and laboratory equipment $ 22,367 $ 16,551 Instruments 13,686 16,796 Office equipment 2,402 2,150 Leasehold improvements 29,280 11,896 Total property and equipment—at cost 67,735 47,393 Less: accumulated depreciation (29,373) (26,974) Property and equipment, net $ 38,362 $ 20,419 Depreciation expense was $5.5 million, $5.9 million, and $5.9 million for the years ended December 31, 2020, 2019, and 2018, respectively. During the years ended December 31, 2020, 2019, and 2018, the Company disposed of certain assets no longer in use with a net book value of approximately $0.5 million in each year, recorded to cost of revenue, sales and marketing, research and development, or general and administrative expenses based on the asset’s respective use.

Marketable Securities

Marketable Securities	12 Months Ended
	Dec. 31, 2020
Investments, Debt and Equity Securities [Abstract]
Marketable securities	5. Marketable Securities The following table summarizes the Company’s marketable securities as of December 31, 2020 and 2019 ( in thousands ): December 31, 2020 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Corporate notes and bonds, short-term $ 22,294 $ 2 $ (2) $ 22,294 U.S. government and agency securities, short-term 14,496 5 — 14,501 International bonds, short-term 4,003 — (1) 4,002 Commercial paper, short-term 46,777 8 — 46,785 Total $ 87,570 $ 15 $ (3) $ 87,582 December 31, 2019 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Corporate notes and bonds, short-term $ 9,099 $ 2 $ (1) $ 9,100 Total $ 9,099 $ 2 $ (1) $ 9,100

Fair Value of Financial Instrum

Fair Value of Financial Instruments	12 Months Ended
	Dec. 31, 2020
Fair Value Disclosures [Abstract]
Fair Value of Financial Instruments	6. Fair Value of Financial Instruments 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 December 31, 2020 and 2019 ( in thousands ): December 31, 2020 Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Total Cash equivalents Money market funds $ 20,077 $ — $ — $ 20,077 Marketable securities Corporate notes and bonds — 22,294 — 22,294 U.S. government and agency securities — 14,501 — 14,501 International bonds — 4,002 — 4,002 Commercial paper — 46,785 — 46,785 Total short-term assets at fair value 20,077 87,582 — 107,659 Long-term marketable securities U.S. government and agency securities — — — — Total assets at fair value $ 20,077 $ 87,582 $ — $ 107,659 December 31, 2019 Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Total Cash equivalents Money market funds $ 19,647 $ — $ — $ 19,647 Marketable securities Corporate notes and bonds — 9,100 — 9,100 Total assets at fair value $ 19,647 $ 9,100 $ — $ 28,747

Long-Term Debt

Long-Term Debt	12 Months Ended
	Dec. 31, 2020
Debt Disclosure [Abstract]
Long-Term Debt	7. Long-Term Debt Term Loans As of December 31, 2020 and 2019, long-term debt consisted of the following ( in thousands ): December 31, 2020 December 31, 2019 Term Loan 70,000 70,000 Final fee obligation 4,865 4,165 Unamortized issuance costs (3,568) (5,020) Total debt, net 71,297 69,145 Current portion of long-term debt — — Long-term debt $ 71,297 $ 69,145 On February 1, 2019 (the “Effective Date”), the Company entered into a Loan and Security Agreement (the “LSA”), with Solar Capital Ltd. and certain other financial institutions (collectively, the “Lenders”). Pursuant to the LSA, the Lenders have provided the Company with a total of $70.0 million in a series of term loans (collectively, the “Term Loans”), of which $50.0 million was funded on the Effective Date, and an additional $20.0 million was funded in December 2019 upon the Company’s achievement of a designated amount of product revenues on a trailing six-month basis. The Term Loans under the LSA 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 Intercontinental Exchange Benchmark Administration, Ltd. 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, 2022 (the “Interest Only Period”). Following the Interest Only Period, 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. Due to the floating per annum rate, the fair value approximates the carrying value of our outstanding Term Loans. Under the 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 LSA. As of December 31, 2020, the Company was in compliance with all covenants under the LSA. The 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 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 LSA immediately due and payable and may exercise the other rights and remedies as set forth in the LSA. Debt Issuance Costs As of December 31, 2020 and 2019, the Company had $3.6 million and $5.0 million, respectively, of unamortized debt issuance discount, which is offset against borrowings in long-term and short-term debt. Amortization of debt issuance costs was $2.3 million, $1.7 million, and $0.9 million for the years ended December 31, 2020, 2019, and 2018, respectively. Amortization of debt issuance costs is included in interest expense in the Company’s consolidated statements of comprehensive loss for the periods presented. Letter of Credit The Company has provided an aggregate of $1.6 million in letters of credit to the landlords of certain of its leased facilities and maintains $42,000 in required minimum account balances with the financial institutions issuing such letters of credit. As a result, the Company maintains $1.6 million of restricted cash in connection with these lease agreements as of December 31, 2020.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	8. Commitments and Contingencies Leases On July 2, 2020, the Company entered into a Single Tenant Industrial Triple Net Lease (the “Lease”), with Icon Owner Pool 1 West/Southwest, LLC, as landlord (the “Landlord”). Pursuant to the Lease, the Company has leased an approximately 73,000 square foot facility in Carlsbad, California (the “Facility”), which the Company may use for manufacturing, research and development, office, and/or distribution purposes. The original term of the Lease runs through June 30, 2031. In addition, subject to the terms and conditions of the Lease, the Landlord has granted the Company an ongoing right of first refusal to lease two additional buildings located adjacent to the Facility. Under the Lease, the Company will pay the Landlord base rent commencing on February 1, 2021 of approximately $0.1 million per month, which base rent amount will increase annually at a rate of 3%. The base rent amount payable by the Company is in addition to “triple net” operating expenses payable by the Company, as set forth in the Lease. In addition, the Company has provided the Landlord a standby letter of credit in the amount of approximately $0.8 million as security for the Company’s full performance of its obligations under the Lease. In connection with entering into the Lease, and subject to the terms and conditions set forth therein, the Landlord has agreed to provide the Company a tenant improvement allowance for the Facility in an amount up to $4.2 million. The Company has operating lease agreements for its office, manufacturing, warehousing and laboratory space. Rent and operating expenses charged under these arrangements was $2.5 million, $2.0 million, and $1.8 million for the years ended December 31, 2020, 2019, and 2018, respectively. The Company reported noncurrent operating lease ROU assets of $8.7 million and $4.6 million, current operating lease liabilities of $3.1 million and $1.8 million, and noncurrent operating lease liabilities of $12.7 million and $5.8 million, respectively, as of December 31, 2020 and 2019. The Company’s operating lease liabilities were measured at a weighted average discount rate of 11.4% and have a weighted average remaining term of 7.9 years. Maturities of our operating lease liabilities as of December 31, 2020 are as follows ( in thousands ): Fiscal Years Ending Operating Leases 2021 $ 3,293 2022 3,509 2023 3,415 2024 2,902 2025 2,266 Thereafter 9,491 Total 24,876 Less: imputed interest (9,034) Total operating lease liabilities $ 15,842

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2020
Stockholders' Equity Attributable to Parent [Abstract]
Stockholders' Equity	9. Stockholders’ Equity On May 6, 2020, the Company entered into an Underwriting Agreement (the “Underwriting Agreement”), with Cowen and Company, LLC and William Blair & Company, LLC acting as joint book-running managers and as representatives of the underwriters named therein (collectively the “Underwriters”) relating to the issuance and sale of 7,253,886 shares of the Company’s common stock (the “Offering”). Under the terms of the Underwriting Agreement, the Company granted the Underwriters an option, exercisable for 30 days, to purchase up to an additional 1,088,082 shares of common stock. The Offering closed on May 11, 2020 and the Company sold 8,341,968 shares of common stock, including the full exercise of the Underwriters' option, at a public offering price of $9.65 per share before underwriting discounts and commissions. The Company raised $80.5 million in gross proceeds from the Offering and incurred $4.8 million in Underwriters’ discounts and commissions and $0.2 million in professional services related to the Offering. On August 5, 2019, the Company entered into an Equity Distribution Agreement (the “Distribution Agreement”) with Canaccord Genuity LLC (“Canaccord”), pursuant to which the Company may offer and sell, from time to time, shares of the Company’s common stock having an aggregate offering price of up to $35.0 million. Under the Distribution Agreement, Canaccord may sell shares by any method deemed to be an “at-the-market” offering as defined in Rule 415 under the U.S. Securities Act of 1933, as amended, or any other method permitted by law, including in privately negotiated transactions. The Company is not obligated to sell any shares under the Distribution Agreement. Canaccord is entitled to a commission of 3% of the aggregate gross proceeds from each sale of shares occurring pursuant to the Distribution Agreement. During the year ended December 31, 2020, the Company sold 363,120 shares of common stock under the Equity Distribution Agreement at a weighted average price per share of $6.13 resulting in aggregate gross proceeds of $2.2 million. The Company incurred $67,000 in commissions paid to Canaccord in connection with such sales. As of December 31, 2020, the Company may issue up to an additional $19.7 million of its common stock under the Distribution Agreement.

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2020
Share-based Payment Arrangement [Abstract]
Stock-Based Compensation	10. Stock-Based Compensation Equity awards may be granted at the discretion of the Compensation Committee of the Board of Directors under the Company's equity plans, in connection with the hiring or retention of personnel and are subject to certain conditions. In May 2020, the Company’s stockholders approved the Company’s 2020 Equity Incentive Plan (“2020 Plan”). Prior to the adoption of the 2020 Plan, the Company granted equity awards under its 2010 Equity Incentive Plan, as amended (“2010 Plan”), which expired in May 2020. The Company recognizes stock-based compensation expense related to stock options, restricted stock units, and market-based stock units granted to employees, directors, and non-employee advisors in exchange for services under the 2020 Plan and 2010 Plan (together the “Equity Plans”) and employee stock purchases under the ESPP. Employee participation in the Equity Plans is at the discretion of the Compensation Committee of the Board of Directors of the Company. Each equity award reduces the number of shares available for grant under the applicable Equity Plan. Stock-based compensation expense is recorded in cost of sales, sales and marketing, research and development, and general and administrative expense based on employees’ respective function. During the years ended December 31, 2020, 2019, and 2018 the Company recognized stock-based compensation expense of $12.8 million, $12.0 million, and $11.7 million, respectively. As of December 31, 2020, there were 4,569,567 shares available for future grant of awards under the 2020 Plan. Stock Options All stock options granted under the Equity Plans 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 stock market on the grant date and generally vest over a period of four ten The Company’s stock option activity for the year ended December 31, 2020 was as follows: Number of Shares Weighted Average Exercise Price Outstanding at December 31, 2019 2,037,132 $ 9.53 Exercised (1,178,431) $ 8.08 Cancelled (15,444) $ 12.07 Outstanding at December 31, 2020 843,257 $ 11.50 Vested and expected to vest at December 31, 2020 843,257 $ 11.50 Exercisable at December 31, 2020 843,257 $ 11.50 There were 843,257 stock options exercisable and outstanding as of December 31, 2020, all of which were granted under the 2010 Plan and which had a remaining weighted average contractual term of 3.4 years and an aggregate intrinsic value of $2.6 million. The Company has recognized all compensation expense related to stock options granted under the 2010 Plan. The Company did not grant any stock options under the 2020 Plan during the year ended December 31, 2020. The intrinsic value of stock options exercised during the years ended December 31, 2020, 2019, and 2018 was $4.8 million, $0.1 million, and $7,000, respectively. Restricted Stock Units Restricted stock units granted under the Equity Plans generally vest over a period of between one four The Company’s restricted stock unit activity for the year ended December 31, 2020 was as follows: Number of Shares Weighted Average Grant Date Fair Value Outstanding at December 31, 2019 2,669,499 $ 6.42 Granted 2,022,136 $ 4.73 Vested (1,512,729) $ 6.48 Cancelled (477,941) $ 5.75 Outstanding at December 31, 2020 2,700,965 $ 5.24 As of December 31, 2020, there was $10.6 million of unrecognized compensation cost related to unvested restricted stock units, which is expected to be recognized over a weighted average period of 2.0 years. The total fair value of restricted stock units that vested during the years ended December 31, 2020, 2019, and 2018 was $15.1 million, $8.7 million, and $5.4 million, respectively. Market-Based Stock Units The Company granted market-based stock units in each of February 2020, 2019, and 2018, which may result in the recipient receiving shares of stock equal up to 200% of the target number of units granted. The vesting and issuance of Company stock pursuant to market-based stock units depends on the Company's stock performance as compared to the NASDAQ Composite Index over the three was $0.9 million 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 1.5 years. The total fair value of market-based stock units that vested during the years ended December 31, 2020, 2019, and 2018 was $1.0 million, $0.8 million, and $0.6 million, respectively. The Company’s market-based stock unit activity for the year ended December 31, 2020 was as follows: Number of Shares Weighted Average Grant Date Fair Value Outstanding at December 31, 2019 454,229 $ 9.40 Granted 321,250 $ 4.39 Vested (189,167) $ 9.32 Cancelled (114,466) $ 8.53 Outstanding at December 31, 2020 471,846 $ 6.32 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 conditions based on simulated future stock prices, with the following assumptions for the years ended December 31, 2020, 2019, and 2018: Years Ended December 31, 2020 2019 2018 Expected volatility 62 % 64 % 65 % Risk-free interest rate 1.16 % 2.50 % 2.40 % Expected dividend — % — % — % Weighted average fair value $ 4.39 $ 10.22 $ 7.19 Employee Stock Purchase Plan The Company’s stockholders originally 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 December 31, 2020, there were 559,336 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 in each of the periods presented. The following table summarizes ESPP activity for the years ended December 31, 2020, 2019, and 2018 ( in thousands, except share and per share data ): Years Ended December 31, 2020 2019 2018 Shares issued 171,580 209,577 252,623 Weighted average fair value of shares issued $ 6.23 $ 4.59 $ 4.20 Employee purchases $ 1,068 $ 962 $ 1,061 The Company uses the Black-Scholes model to estimate the fair value on the grant date for ESPP purchase rights. The following table summarizes the assumptions used in the valuation for the years ended December 31, 2020, 2019, and 2018: Years Ended December 31, 2020 2019 2018 Expected volatility 77.6% - 122.1% 40.0% - 50.0% 54.0% - 73.0% Expected life 6 months 6 months 6 months Risk free rate 0.1% - 0.2% 1.6% - 2.3% 2.1% - 2.6% Expected dividend yield —% —% —% Stock-Based Compensation Expense Recognition Stock-based compensation was recognized in the consolidated statements of comprehensive loss as follows ( in thousands ): Years Ended December 31, 2020 2019 2018 Cost of revenue 830 953 871 Sales and marketing 2,610 3,014 5,549 General and administrative 7,190 6,335 2,807 Research and development 2,166 1,744 2,470 Total stock-based compensation expense $ 12,796 $ 12,046 $ 11,697 The Company did not capitalize stock-based compensation expense during the periods presented and there was no unrecognized tax benefit related to stock-based compensation for any of the years ended December 31, 2020, 2019, or 2018.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Income Taxes	11. Income Taxes The Company’s loss before provision for income taxes for the years ended December 31, 2020, 2019, and 2018, respectively, was generated in the following jurisdictions ( in thousands ): Years Ended December 31, 2020 2019 2018 Domestic $ (19,045) $ (47,807) $ (50,938) Foreign 482 521 577 Total loss before income taxes $ (18,563) $ (47,286) $ (50,361) The components of income tax expense were as follows for the years ended December 31, 2020, 2019, and 2018, respectively ( in thousands ): Years Ended December 31, 2020 2019 2018 Current expense U.S. Federal $ — $ 27 $ 4 State 16 29 43 Foreign 67 11 99 Total current expense 83 67 146 Deferred benefit U.S. Federal (2) (2) (5) State — (1) (2) Total deferred benefit (2) (3) (7) Provision for income taxes $ 81 $ 64 $ 139 The components of net deferred income taxes consisted of the following at December 31, 2020 and 2019, respectively ( in thousands ): December 31, 2020 2019 Deferred income tax assets: NOL and credit carryforwards $ 83,903 $ 84,362 Compensation accruals 4,589 4,669 Accruals and reserves 1,523 764 Operating lease liability 3,746 1,906 State tax provision 4 6 Inventory adjustments 1,722 881 Intangible assets 710 542 Other 2,386 2,031 Gross deferred tax assets 98,583 95,161 Less: valuation allowance (95,495) (92,717) Total deferred tax assets 3,088 2,444 Deferred income tax liabilities: Depreciation 677 951 Contract acquisition costs 359 334 Operating lease right-of-use assets 2,052 1,159 Total deferred tax liabilities 3,088 2,444 Net deferred tax assets (liabilities) $ — $ — A reconciliation of income tax expense to the amount computed by applying the statutory federal income tax rate to the loss from operations is summarized for the years ended December 31, 2020, 2019, and 2018, respectively, as follows: Years Ended December 31, 2020 2019 2018 U.S. Federal statutory income tax rate 21.0 % 21.0 % 21.0 % Permanent differences (0.8) % (0.3) % (0.2) % State taxes 1.7 % 3.8 % 3.0 % Executive compensation limitation (8.8) % (0.9) % (0.5) % Tax reform — % — % 0.1 % Stock-based compensation 3.9 % (1.2) % (2.6) % Rate adjustment (3.1) % — % — % Other 0.5 % 0.1 % 0.1 % Valuation allowance (14.9) % (22.7) % (21.2) % Total tax provision (0.5) % (0.2) % (0.3) % The Company had pre-2018 federal net operating loss (“NOL”) carryforwards available of approximately $264.0 million as of December 31, 2020 after consideration of limitations under Section 382 of the Internal Revenue Code (“Section 382”), as further described below. The federal NOL carryforwards generated prior to 2018 will begin to expire in 2025. The NOLs generated in 2018 and 2019 of approximately $77.8 million will carry forward indefinitely and be available to offset up to 80% of future taxable income each year. Additionally, the Company had state NOL carryforwards available of approximately $243.7 million as of December 31, 2020. The state NOLs may be used to offset future taxable income and have begun to expire. The future utilization of the Company’s NOL carryforwards to offset future taxable income may be subject to a substantial annual limitation as a result of changes in ownership by stockholders that hold 5.0% or more of the Company’s common stock. An assessment of such ownership changes under Section 382 was completed through December 31, 2020. As a result of this assessment, the Company determined that it experienced multiple ownership changes through 2020 which will limit the future utilization of NOL carryforwards. The Company has reduced its deferred tax assets related to NOL carryovers that are anticipated to expire unused as a result of ownership changes. These tax attributes have been excluded from deferred tax assets with a corresponding reduction of the valuation allowance with no net effect on income tax expense or the effective tax rate. Additionally, future ownership changes may further impact the utilization of existing NOLs. The Company has established a full valuation allowance for its deferred tax assets due to uncertainties that preclude it from determining that it is more likely than not that the Company will be able to generate sufficient taxable income to realize such assets. Management assesses the available positive and negative evidence to estimate if sufficient future taxable income will be generated to utilize the existing deferred tax assets. A significant piece of objective negative evidence evaluated was the cumulative loss incurred over the three year period ended December 31, 2020. Such objective evidence limits the ability to consider other subjective evidence, such as the Company’s projections for future growth. Based on this evaluation, as of December 31, 2020, a valuation allowance of $95.5 million has been recorded in order to measure only the portion of the deferred tax asset that more likely than not will be realized. The amount of the deferred tax asset considered realizable, however, could be adjusted if objective negative evidence in the form of cumulative losses is no longer present and additional weight may be given to subjective evidence, such as estimates of future taxable income during carryforward periods and the Company’s projections for growth. The Company applies the two-step approach to recognizing and measuring uncertain tax positions. The first step is to evaluate the tax position for recognition by determining if the weight of available evidence indicates it is more likely than not that the position will be sustained on audit, including resolution of related appeals or litigation processes, if any. The second step is to measure the tax benefit as the largest amount, which is more than 50.0% likely of being realized upon ultimate settlement. Income tax positions must meet a more likely than not recognition threshold at the effective date to be recognized upon the adoption of ASC 740 and in subsequent periods. This interpretation also provides guidance on measurement, derecognition, classification, interest and penalties, accounting in interim periods, disclosure and transition. There were no unrecognized tax benefits for the years ended December 31, 2020, 2019, or 2018. At December 31, 2020 and 2019, the Company had not accrued any interest or penalties related to uncertain tax positions. The Company does not anticipate that there will be a significant change in the amount of unrecognized tax benefits over the next twelve months. The Company recognizes interest and penalties related to uncertain tax positions in income tax expense. The Company is subject to taxation in the United States and 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 December 31, 2020, the Company’s 2014 fiscal year tax return is subject to examination by the United Kingdom tax authorities. 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 the Company has operations, these time periods generally range from three to six years after the year for which the tax return is due or the tax is assessed.

Quarterly Financial Data (Unaud

Quarterly Financial Data (Unaudited)	12 Months Ended
	Dec. 31, 2020
Quarterly Financial Data [Abstract]
Quarterly Financial Data (Unaudited)	12. Quarterly Financial Data (Unaudited) The following table sets forth selected quarterly financial data for the years ended December 31, 2020, 2019, and 2018 ( in thousands except per share data ): 2020 First Quarter Second Quarter Third Quarter Fourth Quarter Total revenue $ 38,742 $ 40,086 $ 42,646 $ 50,080 Gross profit $ 16,152 $ 15,851 $ 16,543 $ 19,398 Loss from operations $ (5,005) $ (2,693) $ (1,266) $ (2,087) Net loss $ (7,008) $ (4,684) $ (3,228) $ (3,724) Net loss per share: Net loss per share—basic and diluted $ (0.12) $ (0.07) $ (0.05) $ (0.05) Weighted average number of shares outstanding—basic and diluted 60,666 66,528 71,103 71,781 2019 First Quarter Second Quarter Third Quarter Fourth Quarter Total revenue $ 21,533 $ 18,374 $ 20,918 $ 27,196 Gross profit $ 5,863 $ 6,573 $ 7,050 $ 9,117 Loss from operations $ (10,910) $ (11,910) $ (10,288) $ (8,706) Net loss $ (12,080) $ (13,308) $ (11,675) $ (10,287) Net loss per share: Net loss per share—basic and diluted $ (0.21) $ (0.23) $ (0.20) $ (0.17) Weighted average number of shares outstanding—basic and diluted 56,581 57,171 57,718 58,915 2018 First Quarter Second Quarter Third Quarter Fourth Quarter Total revenue $ 20,645 $ 14,941 $ 15,795 $ 19,378 Gross profit $ 4,165 $ 4,414 $ 5,630 $ 5,272 Loss from operations $ (10,790) $ (15,802) $ (10,568) $ (10,612) Net loss $ (11,423) $ (16,521) $ (10,993) $ (11,563) Net loss per share: Net loss per share—basic and diluted $ (0.21) $ (0.30) $ (0.20) $ (0.21) Weighted average number of shares outstanding—basic and diluted 55,205 55,547 55,847 56,065

Nature of Operations and Summ_2

Nature of Operations and Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation and Principles of Consolidation	Basis of Presentation and Principles of Consolidation The accompanying consolidated financial statements have been prepared in accordance with United States generally accepted accounting principles (“U.S. GAAP”) and applicable regulations of the U.S. Securities and Exchange Commission (“SEC”). These consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation. In June 2020, the Company made a policy election to reclassify freight revenue from product revenue to other revenue. The Company reclassified freight revenue of $0.7 million and $0.5 million for the years ended December 31, 2019 and 2018, respectively, from product revenue to other revenue to conform with the current year presentation. The reclassification had no impact to total revenue for the periods presented. The Company has experienced net losses since its inception and had an accumulated deficit of $532.9 million as of December 31, 2020. 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 December 31, 2020, the Company had available cash, cash equivalents, and marketable securities of $128.2 million and working capital of $128.8 million 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 these 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.
Revenue	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. Other revenue primarily consists of freight revenue and revenue from extended service agreements. 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 sales and marketing expense 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 determinations based on similar product sales data. The following table represents disaggregated revenue by source ( in thousands ): For the years ended December 31, 2020 2019 2018 Revenue Source ePlex product revenue $ 152,578 $ 59,799 $ 37,601 XT-8 product revenue 16,570 27,022 32,334 Total product revenue 169,148 86,821 69,935 License and other revenue 2,406 1,200 824 Total revenue $ 171,554 $ 88,021 $ 70,759
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. The Company classifies marketable securities as available-for-sale at the time of purchase and reevaluates such classification as of each balance sheet date. All marketable securities are recorded at estimated fair value. Unrealized gains and losses for available-for-sale securities are included in accumulated other comprehensive income, a component of stockholders’ equity. The Company evaluates its marketable securities to assess whether those with unrealized loss positions are other-than-temporarily impaired. Impairments are considered to be other-than-temporary if they are related to deterioration in credit risk or if it is likely that the Company will sell the securities before the recovery of its cost basis. Realized gains and losses and declines in value judged to be other-than-temporary are determined based on the specific identification method and are reported in other income (expense) in the consolidated statements of comprehensive loss. The Company has the ability, if necessary, to liquidate any of its short-term debt securities to meet liquidity needs in the next 12 months. Accordingly, those investments with contractual maturities greater than one year from the date of purchase are classified as short-term investments on the consolidated balance sheets.
Restricted Cash	Restricted Cash Restricted cash represents amounts designated for uses other than current operations and was $1.6 million and $0.8 million at December 31, 2020 and 2019, respectively, which represented an amount held as security for the Company’s facility lease agreements. The following table shows a reconciliation of the Company’s cash and cash equivalents in the consolidated balance sheet to cash, cash equivalents, and restricted cash in the consolidated statement of cash flows as of December 31, 2020 and 2019 ( in thousands ): December 31, 2020 2019 Cash and cash equivalents $ 40,572 $ 44,360 Restricted cash 1,646 758 Total cash, cash equivalents, and restricted cash $ 42,218 $ 45,118
Fair Value of Financial Instruments	Fair Value of Financial 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 carrying amounts of financial instruments such as accounts receivable, prepaid expenses and other current assets, accounts payable, and accrued liabilities approximate the related fair values due to the short-term maturities of these instruments.
Receivables	Receivables Accounts receivable consists of amounts due to the Company from the sale of products and services to customers. Accounts receivable is recognized at amortized cost and is recorded net of an allowance for credit losses. The Company views its accounts receivable as a single portfolio and considers the period of delinquency, historical collection rates, and customer specific-factors in determining its allowance for credit losses.
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.
Product Warranties	Product Warranties The Company generally offers a one
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 - 7 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 includes diagnostic instruments used for sales demonstrations or placed with customers under several types of arrangements, including performance evaluation programs (“PEPs”) and reagent rental agreements. Instruments are placed with customers under PEPs for limited evaluation periods. Instruments are also placed with customers under reagent rental agreements, which generally require customers to purchase a minimum number of test cartridges over the term of the agreement. The Company retains title to the instrument under these arrangements. Maintenance and repair costs are expensed as incurred.
Intangible Assets	Intangible Assets Intangible assets consist of 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
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. The Company did not recognize any impairment of long-lived asset charges during the years ended December 31, 2020, 2019, and 2018.
Employee Benefit Plan	Employee Benefit Plan The Company has a 401(k) tax-deferred savings plan, whereby eligible employees may contribute a percentage of their eligible compensation. The Company makes matching contributions under the 401(k) plan to certain eligible employees.
Leases	Leases The Company determines if an arrangement is a lease at inception. Operating leases are recorded in the consolidated balance sheets as operating lease right-of-use (“ROU”) assets and current and noncurrent operating lease liabilities. Finance leases are recorded in the consolidated balance sheets as other noncurrent assets and other current and noncurrent liabilities. 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 the 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.
Research and Development Costs	Research and Development CostsThe Company expenses all research and development costs in the periods in which they are incurred unless there is alternative future use that supports the capitalization of an asset.
Stock-Based Compensation	Stock-Based Compensation The Company recognizes stock-based compensation expense related to stock options, restricted stock units, market-based stock units, and shares purchased under the Company’s Amended and Restated 2013 Employee Stock Purchase Plan (“ESPP”) granted to employees, non-employees, and directors in exchange for services. The compensation expense is based on the fair value of the applicable award utilizing various assumptions regarding the underlying attributes of the award. The stock-based compensation expense is recorded in cost of revenues, sales and marketing, research and development, and/or general and administrative expenses based on the employee’s respective function. The estimated fair value of stock granted, net of forfeitures expected to occur during the vesting period, is amortized as compensation expense that approximates straight-line expense to reflect vesting as it occurs. The compensation expense related to the grant of restricted stock awards or units is calculated as the fair market value of the stock on the grant date as further adjusted to reflect expected forfeitures. The stock option expense is derived from the Black-Scholes option pricing model that uses several judgment-based variables to calculate the expense. The market-based stock expense is derived from the Monte Carlo Simulation Valuation. The inputs utilized in the valuation of the stock-based awards include the following 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 expected volatility in the Company’s stock price over the expected term of the option or market-based award and is determined by review of the Company’s and similar companies’ historical experience. • Expected Dividend— The valuation methods requires a single expected dividend yield as an input. The Company 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 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 or market-based award.
Foreign Currency Translation	Foreign Currency TranslationThe Company translates the assets and liabilities of the Company’s entities outside the U.S. into U.S. Dollars based on the foreign currency exchange rates at the end of each period. Gains or losses resulting from these foreign currency translations are recorded in accumulated other comprehensive income in the consolidated statement of stockholders’ equity. Foreign currency translation impacts recorded in accumulated other comprehensive income for the years ended December 31, 2020, 2019, and 2018 were $147,000, $11,000, and $44,000, respectively.
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.
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 the years ended December 31, 2020, 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 ): For the years ended December 31, 2020 2019 2018 Options outstanding to purchase common stock 843 2,037 2,440 Other unvested equity awards 3,173 3,124 2,994 Total 4,016 5,161 5,434
Concentration of Risk	Concentration of RiskFinancial instruments which potentially subject the Company to concentrations of credit risk consist primarily of cash, cash equivalents, short-term investment securities, and accounts receivable. The Company limits its exposure to credit loss by placing its cash with high credit quality financial institutions. The Company has established guidelines to diversify its cash and investment securities and their maturities that are intended to secure safety and liquidity.
Comprehensive Loss	Comprehensive LossThe Company has the option to present the total of comprehensive income, the components of net income, and the components of other comprehensive income either in a single continuous statement of comprehensive income or in two separate but consecutive statements. The Company’s comprehensive loss comprises net loss, unrealized gains and losses on available for sale securities, and foreign currency translation.
Recent Accounting Pronouncements	Recently Adopted Accounting Pronouncements In June 2016, the FASB issued ASU 2016-13, Measurement of Credit Losses on Financial Instruments

Nature of Operations and Summ_3

Nature of Operations and Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Disaggregation of Revenue	The following table represents disaggregated revenue by source ( in thousands ): For the years ended December 31, 2020 2019 2018 Revenue Source ePlex product revenue $ 152,578 $ 59,799 $ 37,601 XT-8 product revenue 16,570 27,022 32,334 Total product revenue 169,148 86,821 69,935 License and other revenue 2,406 1,200 824 Total revenue $ 171,554 $ 88,021 $ 70,759
Schedule of Cash and Cash Equivalents	The following table shows a reconciliation of the Company’s cash and cash equivalents in the consolidated balance sheet to cash, cash equivalents, and restricted cash in the consolidated statement of cash flows as of December 31, 2020 and 2019 ( in thousands ): December 31, 2020 2019 Cash and cash equivalents $ 40,572 $ 44,360 Restricted cash 1,646 758 Total cash, cash equivalents, and restricted cash $ 42,218 $ 45,118
Accounts Receivable, Allowance for Credit Loss	The following table summarizes the composition of the allowance for credit losses ( in thousands ): For the years ended December 31, 2020 2019 2018 Beginning balance $ 376 $ 75 $ 2,754 Provision for credit losses, net 17 338 23 Write off of uncollectible accounts (21) (37) (2,702) Ending balance $ 372 $ 376 $ 75
Accrued warranty	The following table summarizes warranty reserve activity ( in thousands ): For the years ended December 31, 2020 2019 2018 Beginning balance $ 279 $ 330 $ 470 Provision 1,508 1,275 1,355 Warranty expenses incurred (1,551) (1,326) (1,495) Ending balance $ 236 $ 279 $ 330
Estimated Useful Lives Of Property 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 - 7 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
Other Current Liabilities	The following table summarizes the composition of current liabilities ( in thousands ): December 31, 2020 2019 Accrued royalties $ 1,863 $ 882 Deferred revenue 508 323 Accrued interest 507 437 Accrued warranties 236 279 Other accrued liabilities 2,136 811 Total other current liabilities $ 5,250 $ 2,732
Schedule of Earnings Per Share, Basic and Diluted	The calculations of diluted net loss per share for the years ended December 31, 2020, 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 ): For the years ended December 31, 2020 2019 2018 Options outstanding to purchase common stock 843 2,037 2,440 Other unvested equity awards 3,173 3,124 2,994 Total 4,016 5,161 5,434

Inventories (Tables)

Inventories (Tables)	12 Months Ended
	Dec. 31, 2020
Inventory Disclosure [Abstract]
Inventories	The following table summarizes the composition of inventory on hand as of December 31, 2020 and 2019 ( in thousands ): December 31, 2020 2019 Raw materials $ 10,087 $ 3,408 Work-in-process 7,958 3,776 Finished goods 3,278 4,117 Total inventories $ 21,323 $ 11,301

Intangible Assets, Net (Tables)

Intangible Assets, Net (Tables)	12 Months Ended
	Dec. 31, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
Summary of intangible assets	The following table summarizes the composition of intangible assets as of December 31, 2020 and 2019 ( in thousands ): December 31, 2020 December 31, 2019 Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount Licensed intellectual property $ 4,750 $ (3,909) $ 841 $ 4,750 $ (3,318) $ 1,432
Summary of estimated future amortization expense	Estimated future amortization expense for these licenses is as follows ( in thousands ): Fiscal Years Ending Future Amortization Expense 2021 $ 591 2022 250 Total $ 841

Property and Equipment, Net (Ta

Property and Equipment, Net (Tables)	12 Months Ended
	Dec. 31, 2020
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	The following table summarizes the composition of property and equipment as of December 31, 2020 and 2019 ( in thousands ) December 31, 2020 December 31, 2019 Property and equipment—at cost: Machinery and laboratory equipment $ 22,367 $ 16,551 Instruments 13,686 16,796 Office equipment 2,402 2,150 Leasehold improvements 29,280 11,896 Total property and equipment—at cost 67,735 47,393 Less: accumulated depreciation (29,373) (26,974) Property and equipment, net $ 38,362 $ 20,419

Marketable Securities (Tables)

Marketable Securities (Tables)	12 Months Ended
	Dec. 31, 2020
Investments, Debt and Equity Securities [Abstract]
Marketable securities, gross unrealized gains/losses	The following table summarizes the Company’s marketable securities as of December 31, 2020 and 2019 ( in thousands ): December 31, 2020 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Corporate notes and bonds, short-term $ 22,294 $ 2 $ (2) $ 22,294 U.S. government and agency securities, short-term 14,496 5 — 14,501 International bonds, short-term 4,003 — (1) 4,002 Commercial paper, short-term 46,777 8 — 46,785 Total $ 87,570 $ 15 $ (3) $ 87,582 December 31, 2019 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Corporate notes and bonds, short-term $ 9,099 $ 2 $ (1) $ 9,100 Total $ 9,099 $ 2 $ (1) $ 9,100

Fair Value of Financial Instr_2

Fair Value of Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2020
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 December 31, 2020 and 2019 ( in thousands ): December 31, 2020 Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Total Cash equivalents Money market funds $ 20,077 $ — $ — $ 20,077 Marketable securities Corporate notes and bonds — 22,294 — 22,294 U.S. government and agency securities — 14,501 — 14,501 International bonds — 4,002 — 4,002 Commercial paper — 46,785 — 46,785 Total short-term assets at fair value 20,077 87,582 — 107,659 Long-term marketable securities U.S. government and agency securities — — — — Total assets at fair value $ 20,077 $ 87,582 $ — $ 107,659 December 31, 2019 Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Total Cash equivalents Money market funds $ 19,647 $ — $ — $ 19,647 Marketable securities Corporate notes and bonds — 9,100 — 9,100 Total assets at fair value $ 19,647 $ 9,100 $ — $ 28,747

Long-Term Debt (Tables)

Long-Term Debt (Tables)	12 Months Ended
	Dec. 31, 2020
Debt Disclosure [Abstract]
Schedule of long-term debt instruments	As of December 31, 2020 and 2019, long-term debt consisted of the following ( in thousands ): December 31, 2020 December 31, 2019 Term Loan 70,000 70,000 Final fee obligation 4,865 4,165 Unamortized issuance costs (3,568) (5,020) Total debt, net 71,297 69,145 Current portion of long-term debt — — Long-term debt $ 71,297 $ 69,145

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Maturities of Operating Lease Liabilities	Maturities of our operating lease liabilities as of December 31, 2020 are as follows ( in thousands ): Fiscal Years Ending Operating Leases 2021 $ 3,293 2022 3,509 2023 3,415 2024 2,902 2025 2,266 Thereafter 9,491 Total 24,876 Less: imputed interest (9,034) Total operating lease liabilities $ 15,842

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2020
Share-based Payment Arrangement [Abstract]
Schedule of share-based compensation, stock options, activity	The Company’s stock option activity for the year ended December 31, 2020 was as follows: Number of Shares Weighted Average Exercise Price Outstanding at December 31, 2019 2,037,132 $ 9.53 Exercised (1,178,431) $ 8.08 Cancelled (15,444) $ 12.07 Outstanding at December 31, 2020 843,257 $ 11.50 Vested and expected to vest at December 31, 2020 843,257 $ 11.50 Exercisable at December 31, 2020 843,257 $ 11.50
Schedule of share-based compensation, restricted stock units, activity	The Company’s restricted stock unit activity for the year ended December 31, 2020 was as follows: Number of Shares Weighted Average Grant Date Fair Value Outstanding at December 31, 2019 2,669,499 $ 6.42 Granted 2,022,136 $ 4.73 Vested (1,512,729) $ 6.48 Cancelled (477,941) $ 5.75 Outstanding at December 31, 2020 2,700,965 $ 5.24
Schedule of share-based compensation, market based stock units, activity	The Company’s market-based stock unit activity for the year ended December 31, 2020 was as follows: Number of Shares Weighted Average Grant Date Fair Value Outstanding at December 31, 2019 454,229 $ 9.40 Granted 321,250 $ 4.39 Vested (189,167) $ 9.32 Cancelled (114,466) $ 8.53 Outstanding at December 31, 2020 471,846 $ 6.32
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 conditions based on simulated future stock prices, with the following assumptions for the years ended December 31, 2020, 2019, and 2018: Years Ended December 31, 2020 2019 2018 Expected volatility 62 % 64 % 65 % Risk-free interest rate 1.16 % 2.50 % 2.40 % Expected dividend — % — % — % Weighted average fair value $ 4.39 $ 10.22 $ 7.19
Schedule of Share-based Compensation, Employee Stock Purchase Plan, Activity	The following table summarizes ESPP activity for the years ended December 31, 2020, 2019, and 2018 ( in thousands, except share and per share data ): Years Ended December 31, 2020 2019 2018 Shares issued 171,580 209,577 252,623 Weighted average fair value of shares issued $ 6.23 $ 4.59 $ 4.20 Employee purchases $ 1,068 $ 962 $ 1,061
Schedule of Share-based Payment Award, Employee Stock Purchase Plan, Valuation Assumptions	The following table summarizes the assumptions used in the valuation for the years ended December 31, 2020, 2019, and 2018: Years Ended December 31, 2020 2019 2018 Expected volatility 77.6% - 122.1% 40.0% - 50.0% 54.0% - 73.0% Expected life 6 months 6 months 6 months Risk free rate 0.1% - 0.2% 1.6% - 2.3% 2.1% - 2.6% Expected dividend yield —% —% —%
Schedule of employee service share-based compensation, allocation of recognized period costs	Stock-based compensation was recognized in the consolidated statements of comprehensive loss as follows ( in thousands ): Years Ended December 31, 2020 2019 2018 Cost of revenue 830 953 871 Sales and marketing 2,610 3,014 5,549 General and administrative 7,190 6,335 2,807 Research and development 2,166 1,744 2,470 Total stock-based compensation expense $ 12,796 $ 12,046 $ 11,697

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Schedule of Income before Income Tax, Domestic and Foreign	The Company’s loss before provision for income taxes for the years ended December 31, 2020, 2019, and 2018, respectively, was generated in the following jurisdictions ( in thousands ): Years Ended December 31, 2020 2019 2018 Domestic $ (19,045) $ (47,807) $ (50,938) Foreign 482 521 577 Total loss before income taxes $ (18,563) $ (47,286) $ (50,361)
Schedule of Components of Income Tax Expense (Benefit)	The components of income tax expense were as follows for the years ended December 31, 2020, 2019, and 2018, respectively ( in thousands ): Years Ended December 31, 2020 2019 2018 Current expense U.S. Federal $ — $ 27 $ 4 State 16 29 43 Foreign 67 11 99 Total current expense 83 67 146 Deferred benefit U.S. Federal (2) (2) (5) State — (1) (2) Total deferred benefit (2) (3) (7) Provision for income taxes $ 81 $ 64 $ 139
Schedule of Deferred Tax Assets and Liabilities	The components of net deferred income taxes consisted of the following at December 31, 2020 and 2019, respectively ( in thousands ): December 31, 2020 2019 Deferred income tax assets: NOL and credit carryforwards $ 83,903 $ 84,362 Compensation accruals 4,589 4,669 Accruals and reserves 1,523 764 Operating lease liability 3,746 1,906 State tax provision 4 6 Inventory adjustments 1,722 881 Intangible assets 710 542 Other 2,386 2,031 Gross deferred tax assets 98,583 95,161 Less: valuation allowance (95,495) (92,717) Total deferred tax assets 3,088 2,444 Deferred income tax liabilities: Depreciation 677 951 Contract acquisition costs 359 334 Operating lease right-of-use assets 2,052 1,159 Total deferred tax liabilities 3,088 2,444 Net deferred tax assets (liabilities) $ — $ —
Schedule of Effective Income Tax Rate Reconciliation	A reconciliation of income tax expense to the amount computed by applying the statutory federal income tax rate to the loss from operations is summarized for the years ended December 31, 2020, 2019, and 2018, respectively, as follows: Years Ended December 31, 2020 2019 2018 U.S. Federal statutory income tax rate 21.0 % 21.0 % 21.0 % Permanent differences (0.8) % (0.3) % (0.2) % State taxes 1.7 % 3.8 % 3.0 % Executive compensation limitation (8.8) % (0.9) % (0.5) % Tax reform — % — % 0.1 % Stock-based compensation 3.9 % (1.2) % (2.6) % Rate adjustment (3.1) % — % — % Other 0.5 % 0.1 % 0.1 % Valuation allowance (14.9) % (22.7) % (21.2) % Total tax provision (0.5) % (0.2) % (0.3) %

Quarterly Financial Data (Una_2

Quarterly Financial Data (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2020
Quarterly Financial Data [Abstract]
Quarterly Financial Information	The following table sets forth selected quarterly financial data for the years ended December 31, 2020, 2019, and 2018 ( in thousands except per share data ): 2020 First Quarter Second Quarter Third Quarter Fourth Quarter Total revenue $ 38,742 $ 40,086 $ 42,646 $ 50,080 Gross profit $ 16,152 $ 15,851 $ 16,543 $ 19,398 Loss from operations $ (5,005) $ (2,693) $ (1,266) $ (2,087) Net loss $ (7,008) $ (4,684) $ (3,228) $ (3,724) Net loss per share: Net loss per share—basic and diluted $ (0.12) $ (0.07) $ (0.05) $ (0.05) Weighted average number of shares outstanding—basic and diluted 60,666 66,528 71,103 71,781 2019 First Quarter Second Quarter Third Quarter Fourth Quarter Total revenue $ 21,533 $ 18,374 $ 20,918 $ 27,196 Gross profit $ 5,863 $ 6,573 $ 7,050 $ 9,117 Loss from operations $ (10,910) $ (11,910) $ (10,288) $ (8,706) Net loss $ (12,080) $ (13,308) $ (11,675) $ (10,287) Net loss per share: Net loss per share—basic and diluted $ (0.21) $ (0.23) $ (0.20) $ (0.17) Weighted average number of shares outstanding—basic and diluted 56,581 57,171 57,718 58,915 2018 First Quarter Second Quarter Third Quarter Fourth Quarter Total revenue $ 20,645 $ 14,941 $ 15,795 $ 19,378 Gross profit $ 4,165 $ 4,414 $ 5,630 $ 5,272 Loss from operations $ (10,790) $ (15,802) $ (10,568) $ (10,612) Net loss $ (11,423) $ (16,521) $ (10,993) $ (11,563) Net loss per share: Net loss per share—basic and diluted $ (0.21) $ (0.30) $ (0.20) $ (0.21) Weighted average number of shares outstanding—basic and diluted 55,205 55,547 55,847 56,065

Nature of Operations and Summ_4

Nature of Operations and Summary of Significant Accounting Policies - Revenue disaggregation (Details) - USD ($) $ in Thousands	3 Months Ended												12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disaggregation of Revenue
Product revenue													$ 169,148	$ 86,821	$ 69,935
License and other revenue													2,406	1,200	824
Total revenue	$ 50,080	$ 42,646	$ 40,086	$ 38,742	$ 27,196	$ 20,918	$ 18,374	$ 21,533	$ 19,378	$ 15,795	$ 14,941	$ 20,645	171,554	88,021	70,759
ePlex Revenue
Disaggregation of Revenue
Product revenue													152,578	59,799	37,601
XT-8 Revenue
Disaggregation of Revenue
Product revenue													$ 16,570	$ 27,022	$ 32,334

Nature of Operations and Summ_5

Nature of Operations and Summary of Significant Accounting Policies - Receivables (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	$ 376	$ 75	$ 2,754
Provision for bad debt, net of recoveries	17	338	23
Write off of uncollectible accounts	(21)	(37)	(2,702)
Ending balance	$ 372	$ 376	$ 75

Nature of Operations and Summ_6

Nature of Operations and Summary of Significant Accounting Policies - Product Warranties (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Movement in Standard Product Warranty Accrual [Roll Forward]
Beginning balance	$ 279	$ 330	$ 470
Provision	1,508	1,275	1,355
Warranty expenses incurred	(1,551)	(1,326)	(1,495)
Ending balance	$ 236	$ 279	$ 330

Nature of Operations and Summ_7

Nature of Operations and Summary of Significant Accounting Policies - Property and equipment (Details)	12 Months Ended
	Dec. 31, 2020
Machinery and laboratory equipment | Minimum
Property and Equipment
Property, plant and equipment, estimated useful lives	3 years
Machinery and laboratory equipment | Maximum
Property and Equipment
Property, plant and equipment, estimated useful lives	5 years
Instruments | Minimum
Property and Equipment
Property, plant and equipment, estimated useful lives	4 years
Instruments | Maximum
Property and Equipment
Property, plant and equipment, estimated useful lives	7 years
Office equipment | Minimum
Property and Equipment
Property, plant and equipment, estimated useful lives	3 years
Office equipment | Maximum
Property and Equipment
Property, plant and equipment, estimated useful lives	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

Nature of Operations and Summ_8

Nature of Operations and Summary of Significant Accounting Policies - Net Loss Per Common Share (Details) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Antidilutive securities excluded from calculation	4,016	5,161	5,434
Employee Stock Option
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Antidilutive securities excluded from calculation	843	2,037	2,440
Restricted Stock Awards
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Antidilutive securities excluded from calculation	3,173	3,124	2,994

Nature of Operations and Summ_9

Nature of Operations and Summary of Significant Accounting Policies - Concentration Risk (Details) - customer	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Concentration Risk [Line Items]
Number of customers	0	2
Revenue Benchmark | Customer Concentration Risk
Concentration Risk [Line Items]
Concentration risk, percentage	10.00%	14.00%	16.00%
Accounts Receivable | Customer Concentration Risk | Customer A
Concentration Risk [Line Items]
Concentration risk, percentage		24.00%
Accounts Receivable | Customer Concentration Risk | Customer B
Concentration Risk [Line Items]
Concentration risk, percentage		11.00%

Nature of Operations and Sum_10

Nature of Operations and Summary of Significant Accounting Policies - Additional information (Details Textual) $ in Thousands	12 Months Ended
	Dec. 31, 2020USD ($)segment	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Prior period reclassification adjustment		$ 700	$ 500
Accumulated deficit	$ (532,877)	(514,233)
Cash, cash equivalents, and marketable securities	128,200
Working capital	$ 128,800
Sufficient capital to fund its operations	one
Number of reportable segments | segment	1
Restricted cash	$ 1,646	758
Cash and cash equivalents	40,572	44,360
Total cash, cash equivalents, and restricted cash	$ 42,218	45,118	37,044	$ 27,512
Warranty coverage period, instruments	1 year
Warranty coverage period, consumable goods	60 days
Finite-lived intangible asset, useful life	10 years
Accrued royalties	$ 1,863	882
Deferred revenue	508	323
Accrued interest	507	437
Accrued warranties	236	279
Other accrued liabilities	2,136	811
Total other current liabilities	5,250	2,732
Foreign currency translation adjustments, net of tax	$ 147	$ 11	$ 44

Inventories (Details)

Inventories (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Summary of inventory on hand
Raw materials	$ 10,087	$ 3,408
Work-in-process	7,958	3,776
Finished goods	3,278	4,117
Total inventories	$ 21,323	$ 11,301

Intangible Assets, Net - Compon

Intangible Assets, Net - Components of gross and net intangible asset balances (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Finite-lived intangible assets
Net carrying amount	$ 841
Finite-lived intangible assets, remaining amortization period	1 year 4 months 24 days
Amortization of intangible assets	$ 600	$ 600
Intellectual Property
Finite-lived intangible assets
Gross carrying amount	4,750	4,750
Accumulated amortization	(3,909)	(3,318)
Net carrying amount	$ 841	$ 1,432

Intangible Assets, Net - Future

Intangible Assets, Net - Future amortization expense (Details) $ in Thousands	Dec. 31, 2020USD ($)
Summary of estimated future amortization expense
2021	$ 591
2022	250
Net carrying amount	$ 841

Property and Equipment, Net (De

Property and Equipment, Net (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Property and Equipment
Property and equipment	$ 67,735	$ 47,393
Less: accumulated depreciation	(29,373)	(26,974)
Property and equipment, net	38,362	20,419
Machinery and laboratory equipment
Property and Equipment
Property and equipment	22,367	16,551
Instruments
Property and Equipment
Property and equipment	13,686	16,796
Office equipment
Property and Equipment
Property and equipment	2,402	2,150
Leasehold improvements
Property and Equipment
Property and equipment	$ 29,280	$ 11,896

Property and Equipment, Net (Na

Property and Equipment, Net (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Abstract]
Depreciation	$ 5.5	$ 5.9	$ 5.9
Property, plant and equipment, disposals	$ 0.5	$ 0.5	$ 0.5

Marketable Securities - Gross u

Marketable Securities - Gross unrealized gains/losses (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Marketable securities
Amortized Cost	$ 87,570
Gross Unrealized Gains	15
Gross Unrealized Losses	(3)
Estimated Fair Value	87,582
Due in one year or less
Marketable securities
Amortized Cost		$ 9,099
Gross Unrealized Gains		2
Gross Unrealized Losses		(1)
Estimated Fair Value		9,100
Corporate notes and bonds, short-term
Marketable securities
Estimated Fair Value	22,294	9,100
Corporate notes and bonds, short-term | Due in one year or less
Marketable securities
Amortized Cost	22,294	9,099
Gross Unrealized Gains	2	2
Gross Unrealized Losses	(2)	(1)
Estimated Fair Value	22,294	$ 9,100
US Government Corporations and Agencies Securities
Marketable securities
Estimated Fair Value	0
US Government Corporations and Agencies Securities | Due in one year or less
Marketable securities
Amortized Cost	14,496
Gross Unrealized Gains	5
Gross Unrealized Losses	0
Estimated Fair Value	14,501
International bonds
Marketable securities
Estimated Fair Value	4,002
International bonds | Due in one year or less
Marketable securities
Amortized Cost	4,003
Gross Unrealized Gains	0
Gross Unrealized Losses	(1)
Estimated Fair Value	4,002
Commercial Paper
Marketable securities
Estimated Fair Value	46,785
Commercial Paper | Due in one year or less
Marketable securities
Amortized Cost	46,777
Gross Unrealized Gains	8
Gross Unrealized Losses	0
Estimated Fair Value	$ 46,785

Fair Value of Financial Instr_3

Fair Value of Financial Instruments - Fair value hierarchy (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Fair value, assets measured on a recurring basis
Marketable securities	$ 87,582
Total short-term assets at fair value	107,659
Total assets, fair value	107,659	$ 28,747
Due in one year or less
Fair value, assets measured on a recurring basis
Marketable securities		9,100
Level 1
Fair value, assets measured on a recurring basis
Total short-term assets at fair value	20,077
Total assets, fair value	20,077	19,647
Level 2
Fair value, assets measured on a recurring basis
Total short-term assets at fair value	87,582
Total assets, fair value	87,582	9,100
Level 3
Fair value, assets measured on a recurring basis
Total short-term assets at fair value	0
Total assets, fair value	0	0
Money Market Funds
Fair value, assets measured on a recurring basis
Cash equivalents	20,077	19,647
Money Market Funds | Level 1
Fair value, assets measured on a recurring basis
Cash equivalents	20,077	19,647
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, short-term
Fair value, assets measured on a recurring basis
Marketable securities	22,294	9,100
Corporate notes and bonds, short-term | Due in one year or less
Fair value, assets measured on a recurring basis
Marketable securities	22,294	9,100
Corporate notes and bonds, short-term | Level 1
Fair value, assets measured on a recurring basis
Marketable securities	0	0
Corporate notes and bonds, short-term | Level 2
Fair value, assets measured on a recurring basis
Marketable securities	22,294	9,100
Corporate notes and bonds, short-term | Level 3
Fair value, assets measured on a recurring basis
Marketable securities	0	$ 0
US Government Corporations and Agencies Securities
Fair value, assets measured on a recurring basis
Marketable securities	0
US Government Corporations and Agencies Securities | Due in one year or less
Fair value, assets measured on a recurring basis
Marketable securities	14,501
US Government Corporations and Agencies Securities | Level 1
Fair value, assets measured on a recurring basis
Marketable securities	0
US Government Corporations and Agencies Securities | Level 1 | Due in one year or less
Fair value, assets measured on a recurring basis
Marketable securities	0
US Government Corporations and Agencies Securities | Level 2
Fair value, assets measured on a recurring basis
Marketable securities	0
US Government Corporations and Agencies Securities | Level 2 | Due in one year or less
Fair value, assets measured on a recurring basis
Marketable securities	14,501
US Government Corporations and Agencies Securities | Level 3
Fair value, assets measured on a recurring basis
Marketable securities	0
US Government Corporations and Agencies Securities | Level 3 | Due in one year or less
Fair value, assets measured on a recurring basis
Marketable securities	0
International bonds
Fair value, assets measured on a recurring basis
Marketable securities	4,002
International bonds | Due in one year or less
Fair value, assets measured on a recurring basis
Marketable securities	4,002
International bonds | Level 1
Fair value, assets measured on a recurring basis
Marketable securities	0
International bonds | Level 2
Fair value, assets measured on a recurring basis
Marketable securities	4,002
International bonds | Level 3
Fair value, assets measured on a recurring basis
Marketable securities	0
Commercial Paper
Fair value, assets measured on a recurring basis
Marketable securities	46,785
Commercial Paper | Due in one year or less
Fair value, assets measured on a recurring basis
Marketable securities	46,785
Commercial Paper | Level 1
Fair value, assets measured on a recurring basis
Marketable securities	0
Commercial Paper | Level 2
Fair value, assets measured on a recurring basis
Marketable securities	46,785
Commercial Paper | Level 3
Fair value, assets measured on a recurring basis
Marketable securities	$ 0

Long-Term Debt - Term loans and

Long-Term Debt - Term loans and line of credit (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Jul. 02, 2020	Dec. 16, 2019	Feb. 01, 2019
Debt Instrument
Final fee obligation	$ 4,865,000	$ 4,165,000
Unamortized issuance costs	(3,568,000)	(5,020,000)
Long-term debt	$ 71,297,000	69,145,000
Term loans, debt facility, maximum borrowing capacity						$ 70,000,000
Debt instrument, maturity date	Feb. 1, 2023
Amortization of deferred debt issuance costs	$ 2,253,000	1,740,000	$ 938,000
Letters of credit outstanding, amount	1,600,000			$ 800,000
Restricted cash requirement	42,000
Restricted cash	$ 1,646,000	758,000
Base Rate [Member]
Debt Instrument
Debt instrument, basis spread on variable rate	2.51%
London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument
Debt instrument, basis spread on variable rate	5.90%
Term Loans
Debt Instrument
Amortization of deferred debt issuance costs	$ 2,300,000	1,700,000	$ 900,000
Term Loan
Debt Instrument
Term Loan	70,000,000	70,000,000
Total debt, net	70,000,000	70,000,000
Total debt, net
Debt Instrument
Term Loan	71,297,000	69,145,000
Total debt, net	71,297,000	69,145,000
Current portion of long-term debt	0	0
Long-term debt	$ 71,297,000	$ 69,145,000
Tranche 1 Loan
Debt Instrument
Term loans, debt facility, maximum borrowing capacity						$ 50,000,000
Debt instrument, interest only period end	Feb. 28, 2022
Tranche 2 Loan
Debt Instrument
Term loans, debt facility, maximum borrowing capacity					$ 20,000,000

Commitments and Contingencies -

Commitments and Contingencies - Future minimum lease payments (Details) $ in Thousands	Dec. 31, 2020USD ($)
Schedule of future minimum lease payments
2021	$ 3,293
2022	3,509
2023	3,415
2024	2,902
2025	2,266
Thereafter	9,491
Total	24,876
Less: imputed interest	(9,034)
Total operating lease liabilities	$ 15,842

Commitments and Contingencies_2

Commitments and Contingencies - Additional information (Details) ft² in Thousands, $ in Thousands	Jul. 02, 2020USD ($)	Dec. 31, 2020USD ($)ft²Rate	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Commitments and Contingencies Disclosure [Abstract]
Operating lease, square feet | ft²		73
Operating lease, cost	$ 100
Operating lease, annual rent increase	3.00%
Letters of credit outstanding, amount	$ 800	$ 1,600
Payments for (proceeds from) tenant allowance	$ 4,200
Lease, cost		2,500	$ 2,000	$ 1,800
Operating lease, right-of-use asset		8,676	4,642
Operating lease, liability, current		3,093	1,842
Operating lease, liability, noncurrent		$ 12,749	$ 5,796
Operating lease, weighted average discount rate, percent | Rate		11.40%
Operating lease, weighted average remaining lease term		7 years 10 months 24 days

Stockholders' Equity (Details)

Stockholders' Equity (Details) - USD ($) $ / shares in Units, $ in Thousands	May 11, 2020	May 06, 2020	Dec. 31, 2020	Aug. 05, 2020
Type of Issuance Cost [Line Items]
Issuance of common stock, net of offering costs (in shares)			363,120
Shares issued, price per share (in dollars per share)	$ 9.65
Proceeds from issuance or sale of equity	$ 80,500
Payments of stock issuance costs			$ 67
Maximum atm offering amount				$ 35,000
Underwriters commission				3.00%
Weighted average price per share (in dollars per share)			$ 6.13
Gross proceeds from issuance of common stock			$ 2,200
Common stock available for future issuance			$ 19,700
Public Offering Shares Excluding Underwriters' Option
Type of Issuance Cost [Line Items]
Issuance of common stock, net of offering costs (in shares)		7,253,886
Shares Attributable to Underwriters' Option
Type of Issuance Cost [Line Items]
Issuance of common stock, net of offering costs (in shares)		1,088,082
Public Offering Shares, Including Underwriters' Option
Type of Issuance Cost [Line Items]
Issuance of common stock, net of offering costs (in shares)	8,341,968
Issuance Costs Due To Underwriters
Type of Issuance Cost [Line Items]
Payments of stock issuance costs	$ 4,800
Issuance Costs Due to Additional Parties
Type of Issuance Cost [Line Items]
Payments of stock issuance costs	$ 200

Stock-Based Compensation - Stoc

Stock-Based Compensation - Stock Options Activity (Details) - 2010 Equity Incentive Plan - Employee Stock Option	12 Months Ended
	Dec. 31, 2020$ / sharesshares
Stock Appreciation Rights Activity
Options, outstanding at December 31, 2019, weighted average exercise price | shares	2,037,132
Options, exercised, shares | shares	(1,178,431)
Options, cancelled, shares | shares	(15,444)
Options, outstanding at December 31, 2020, shares | shares	843,257
Options, vested and expected to vest, shares | shares	843,257
Weighted Average Grant Date Fair Value
Options, outstanding at December 31, 2019, weighted average exercise price | $ / shares	$ 9.53
Options, exercised, weighted average exercise price | $ / shares	8.08
Options, cancelled, weighted average exercise price | $ / shares	12.07
Options, outstanding at December 31, 2020, weighted average exercise price | $ / shares	11.50
Options, vested and expected to vest, weighted average exercise price | $ / shares	$ 11.50
Options, exercisable, shares | shares	843,257
Options, exercisable, weighted average exercise price | $ / shares	$ 11.50

Stock-Based Compensation - Rest

Stock-Based Compensation - Restricted Stock Units (Details) - 2010 Equity Incentive Plan - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Weighted Average Grant Date Fair Value
Vested, weighted average grant date fair value	$ 6.23	$ 4.59	$ 4.20
Restricted Stock Units (RSUs)
Stock Appreciation Rights Activity
Outstanding at December 31, 2019, shares	2,669,499
Granted, shares	2,022,136
Vested, shares	(1,512,729)
Cancelled, shares	(477,941)
Outstanding at December 31, 2020, shares	2,700,965	2,669,499
Weighted Average Grant Date Fair Value
Outstanding at December 31, 2019, weighted average grant date fair value	$ 6.42
Granted, weighted average grant date fair value	4.73
Vested, weighted average grant date fair value	6.48
Cancelled, weighted average grant date fair value	5.75
Outstanding at December 31, 2020, weighted average grant date fair value	$ 5.24	$ 6.42

Stock-Based Compensation - Mark

Stock-Based Compensation - Market-Based Stock Unit Activity (Details) - 2010 Equity Incentive Plan - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Weighted Average Grant Date Fair Value
Vested, weighted average grant date fair value	$ 6.23	$ 4.59	$ 4.20
Market-based share unit
Stock Appreciation Rights Activity
Outstanding at December 31, 2019, shares	454,229
Granted, shares	321,250
Vested, shares	(189,167)
Cancelled, shares	(114,466)
Outstanding at December 31, 2020, shares	471,846	454,229
Weighted Average Grant Date Fair Value
Outstanding at December 31, 2019, weighted average grant date fair value	$ 9.40
Granted, weighted average grant date fair value	4.39	$ 10.22	$ 7.19
Vested, weighted average grant date fair value	9.32
Cancelled, weighted average grant date fair value	8.53
Outstanding at December 31, 2020, weighted average grant date fair value	$ 6.32	$ 9.40

Stock-Based Compensation - Valu

Stock-Based Compensation - Valuation Assumptions (Details) - Market-based share unit - 2010 Equity Incentive Plan - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility	62.00%	64.00%	65.00%
Risk-free interest rate	1.16%	2.50%	2.40%
Expected dividend	0.00%	0.00%	0.00%
Weighted average fair value	$ 4.39	$ 10.22	$ 7.19

Stock-Based Compensation - Empl

Stock-Based Compensation - Employee Stock Purchase Plan (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee purchases	$ 1,068	$ 962	$ 1,061
2010 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issued	171,580	209,577	252,623
Weighted average fair value of shares issued	$ 6.23	$ 4.59	$ 4.20
Employee purchases	$ 1,068	$ 962	$ 1,061
2013 Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected life	6 months	6 months	6 months
Expected dividend	0.00%	0.00%	0.00%
2013 Employee Stock Purchase Plan | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility	77.60%	40.00%	54.00%
Risk-free interest rate	0.10%	1.60%	2.10%
2013 Employee Stock Purchase Plan | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility	122.10%	50.00%	73.00%
Risk-free interest rate	0.20%	2.30%	2.60%

Stock-Based Compensation - Expe

Stock-Based Compensation - Expense recognition (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	$ 12,796	$ 12,046	$ 11,697
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	830	953	871
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	2,610	3,014	5,549
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	7,190	6,335	2,807
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	$ 2,166	$ 1,744	$ 2,470

Stock-Based Compensation - Narr

Stock-Based Compensation - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	May 22, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	$ 12,796,000	$ 12,046,000	$ 11,697,000
Number of shares available for grant	4,569,567
Options, outstanding, intrinsic value	$ 4,800,000	100,000	7,000
Equity award other than options, vested in period, fair value	$ 1,000,000	800,000	600,000
2010 Equity Incentive Plan | Market-based share unit
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	3 years
Nonvested award, compensation cost not yet recognized	$ 900,000
Nonvested award, compensation cost not yet recognized, weighted average period for recognition	1 year 6 months
Maximum msu payout percentage	200.00%
2010 Equity Incentive Plan | Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Nonvested award, compensation cost not yet recognized	$ 10,600,000
Nonvested award, compensation cost not yet recognized, weighted average period for recognition	2 years
Equity award other than options, vested in period, fair value	$ 15,100,000	$ 8,700,000	$ 5,400,000
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 | Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	4 years
Award expiration period	10 years
Options, outstanding at December 31, 2020, weighted average exercise price	843,257	2,037,132
Options, outstanding, weighted average remaining contractual term	3 years 4 months 24 days
Options, outstanding, intrinsic value	$ 2,600,000
2013 Employee Stock Purchase Plan | Employee stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares available for grant	559,336
Number of shares authorized				650,000
Discount from market price, offering date	85.00%
Maximum employee subscription rate	10.00%
Maximum number of shares per employee	1,500
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

Income Taxes - Jurisdiction (De

Income Taxes - Jurisdiction (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Domestic	$ (19,045)	$ (47,807)	$ (50,938)
Foreign	482	521	577
Loss before income taxes	$ (18,563)	$ (47,286)	$ (50,361)

Income Taxes - Income Tax Expen

Income Taxes - Income Tax Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Current expense
U.S. Federal	$ 0	$ 27	$ 4
State	16	29	43
Foreign	67	11	99
Total current expense	83	67	146
Deferred benefit
U.S. Federal	(2)	(2)	(5)
State	0	(1)	(2)
Total deferred benefit	(2)	(3)	(7)
Provision for income taxes	$ 81	$ 64	$ 139

Income Taxes - Deferred Income

Income Taxes - Deferred Income Taxes (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Deferred income tax assets:
NOL and credit carryforwards	$ 83,903	$ 84,362
Compensation accruals	4,589	4,669
Accruals and reserves	1,523	764
Operating lease liability	3,746	1,906
State tax provision	4	6
Inventory adjustments	1,722	881
Intangible assets	710	542
Other	2,386	2,031
Gross deferred tax assets	98,583	95,161
Less: valuation allowance	(95,495)	(92,717)
Total deferred tax assets	3,088	2,444
Deferred income tax liabilities:
Depreciation	677	951
Contract acquisition costs	359	334
Operating lease right-of-use assets	2,052	1,159
Total deferred tax liabilities	3,088	2,444
Net deferred tax assets (liabilities)	$ 0	$ 0

Income Taxes - Reconciliation (

Income Taxes - Reconciliation (Details)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
U.S. Federal statutory income tax rate	21.00%	21.00%	21.00%
Permanent differences	(0.80%)	(0.30%)	(0.20%)
State taxes	1.70%	3.80%	3.00%
Executive compensation limitation	(8.80%)	(0.90%)	(0.50%)
Tax reform	0.00%	0.00%	0.10%
Stock-based compensation	3.90%	(1.20%)	(2.60%)
Rate adjustment	(3.10%)	0.00%	0.00%
Other	0.50%	0.10%	0.10%
Valuation allowance	(14.90%)	(22.70%)	(21.20%)
Total tax provision	(0.50%)	(0.20%)	(0.30%)

Income Taxes - Narrative (Detai

Income Taxes - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Operating Loss Carryforwards [Line Items]
Less: valuation allowance	$ 95,495	$ 92,717
Probability of realization of income tax upon settlement	50.00%
State and Local Jurisdiction
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	$ 243,700
Pre-2018 NOL | Domestic Tax Authority
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	264,000
Post-2018 NOL | Domestic Tax Authority
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	$ 77,800

Quarterly Financial Data (Una_3

Quarterly Financial Data (Unaudited) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended												12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Quarterly Financial Data [Abstract]
Total revenue	$ 50,080	$ 42,646	$ 40,086	$ 38,742	$ 27,196	$ 20,918	$ 18,374	$ 21,533	$ 19,378	$ 15,795	$ 14,941	$ 20,645	$ 171,554	$ 88,021	$ 70,759
Gross profit	19,398	16,543	15,851	16,152	9,117	7,050	6,573	5,863	5,272	5,630	4,414	4,165	67,944	28,603	19,481
Loss from operations	(2,087)	(1,266)	(2,693)	(5,005)	(8,706)	(10,288)	(11,910)	(10,910)	(10,612)	(10,568)	(15,802)	(10,790)	(11,051)	(41,814)	(47,772)
Net loss	$ (3,724)	$ (3,228)	$ (4,684)	$ (7,008)	$ (10,287)	$ (11,675)	$ (13,308)	$ (12,080)	$ (11,563)	$ (10,993)	$ (16,521)	$ (11,423)	$ (18,644)	$ (47,350)	$ (50,500)
Net loss per share—basic and diluted	$ (0.05)	$ (0.05)	$ (0.07)	$ (0.12)	$ (0.17)	$ (0.20)	$ (0.23)	$ (0.21)	$ (0.21)	$ (0.20)	$ (0.30)	$ (0.21)	$ (0.28)	$ (0.82)	$ (0.91)
Weighted average number of shares outstanding—basic and diluted	71,781	71,103	66,528	60,666	58,915	57,718	57,171	56,581	56,065	55,847	55,547	55,205	67,541	57,603	55,669