nLIGHT (LASR) 10-Q 9 May 19 2019 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2019	May 03, 2019
Document and Entity Information [Abstract]
Entity Registrant Name	nLIGHT, Inc.
Entity Central Index Key	0001124796
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Document Type	10-Q
Document Period End Date	Mar. 31, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q1
Amendment Flag	false
Smaller Reporting Company	false
Emerging Growth	true
Entity Ex Transition Period	false
Entity Common Stock, Shares Outstanding		37,004,846

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 142,366	$ 149,478
Accounts receivable, net of allowances of $330 and $303	30,160	26,528
Inventory	40,846	35,329
Prepaid expenses and other current assets	5,822	7,286
Total current assets	219,194	218,621
Property and equipment, net of accumulated depreciation of $54,874 and $53,812	22,135	21,462
Intangible assets, net of accumulated amortization of $2,213 and $2,049	2,786	2,686
Goodwill	1,387	1,387
Other assets	6,029	5,974
Total assets	251,531	250,130
Current liabilities:
Accounts payable	13,986	12,068
Accrued liabilities	9,831	10,708
Customer advances	88	493
Deferred revenue	61	227
Current portion of long-term debt	102	91
Total current liabilities	24,068	23,587
Non-current income taxes payable	6,817	6,472
Long-term debt	19	18
Other long-term liabilities	1,964	2,270
Total liabilities	32,868	32,347
Stockholders' equity:
Preferred stock - $0.0001 par value; 5,000 shares authorized, zero shares issued and outstanding at March 31, 2019 and December 31, 2018.	0	0
Common stock - $0.0001 par value; 190,000 shares authorized, 36,906 shares issued and outstanding at March 31, 2019 and 190,000 shares authorized, 36,705 shares issued and outstanding at December 31, 2018.	15	15
Additional paid-in capital	326,870	324,656
Accumulated other comprehensive loss	(2,417)	(2,157)
Accumulated deficit	(105,805)	(104,731)
Total stockholders’ equity	218,663	217,783
Total liabilities and stockholders’ equity	$ 251,531	$ 250,130

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) shares in Thousands, $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Statement of Financial Position [Abstract]
Accounts receivable, allowances	$ 330	$ 303
Property and equipment, accumulated depreciation	54,874	53,812
Intangible assets, accumulated amortization	$ 2,213	$ 2,049
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred stock, shares authorized (in shares)	5,000	5,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	190,000	190,000
Common stock, shares issued (in shares)	36,906	36,705
Common stock, shares outstanding (in shares)	36,906	36,705

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Income Statement [Abstract]
Revenues	$ 41,861	$ 42,467
Cost of revenues	28,347	27,738
Gross profit	13,514	14,729
Operating expenses:
Research and development	6,422	4,283
Sales, general, and administrative	8,144	6,238
Total operating expenses	14,566	10,521
Income (loss) from operations	(1,052)	4,208
Other income (expense):
Interest income (expense), net	750	(219)
Other income, net	820	76
Income before income taxes	518	4,065
Income tax expense	1,753	1,149
Net income (loss)	(1,235)	2,916
Less: Income allocated to participating securities	0	(2,916)
Net income (loss) attributable to common stockholders	$ (1,235)	$ 0
Net income (loss) per share, basic (in dollars per share)	$ (0.03)	$ 0
Net income (loss) per share, diluted (in dollars per share)	$ (0.03)	$ 0
Shares used in per share calculations:
Basic (in shares)	36,694	3,031
Diluted (in shares)	36,694	3,031

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ (1,235)	$ 2,916
Other comprehensive income (loss):
Foreign currency translation adjustments, net of tax	(260)	950
Comprehensive income (loss)	$ (1,495)	$ 3,866

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Cash flows from operating activities:
Net income (loss)	$ (1,235)	$ 2,916
Adjustments to reconcile net income (loss) to net cash used in operating activities:
Depreciation	1,565	1,434
Amortization	647	512
Provision for losses on accounts receivable	28	40
Stock-based compensation	1,909	162
Loss on disposal of property and equipment	5	13
Changes in operating assets and liabilities:
Accounts receivable, net	(3,582)	(4,689)
Inventory	(6,072)	(5,127)
Prepaid expenses and other current assets	1,500	(1,058)
Other assets	(588)	(285)
Accounts payable	2,113	2,701
Accrued and other long-term liabilities	(996)	(1,366)
Customer advances	(412)	166
Deferred revenue	(166)	156
Non-current income taxes payable	345	255
Net cash used in operating activities	(4,939)	(4,170)
Cash flows from investing activities:
Purchases of property, equipment and intangibles	(2,734)	(3,390)
Net cash used in investing activities	(2,734)	(3,390)
Cash flows from financing activities:
Principal payments on debt and capital leases	(25)	(29)
Payments of other financing costs	0	(521)
Proceeds from stock option exercises	467	61
Net cash provided by (used in) financing activities	442	(489)
Effect of exchange rate changes on cash	119	(16)
Net decrease in cash and cash equivalents	(7,112)	(8,065)
Cash and cash equivalents, beginning of period	149,478	36,687
Cash and cash equivalents, end of period	142,366	28,622
Supplemental disclosures:
Cash paid (received) for interest	(769)	252
Cash paid for income taxes	813	990
Accrued purchases of property, equipment and intangibles	835	1,380
Accrued deferred offering costs	$ 0	$ 797

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Preferred stock	Preferred stockConvertible preferred stock	Common stock	Additional paid-in capital	Accumulated other comprehensive loss	Accumulated deficit
Preferred stock, shares outstanding, beginning balance (in shares) at Dec. 31, 2017			24,642
Preferred stock, beginning balance at Dec. 31, 2017			$ 12
Common stock, shares outstanding, beginning balance (in shares) at Dec. 31, 2017				2,979
Common stock, beginning balance at Dec. 31, 2017	$ 61,283			$ 2	$ 180,657	$ (719)	$ (118,669)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	2,916						2,916
Exercise of stock options (in shares)				77
Exercise of stock options	61				61
Stock-based compensation	162				162
Deferred offering costs	(787)
Cumulative translation adjustment	950					950
Preferred stock, shares outstanding, ending balance (in shares) at Mar. 31, 2018			24,642
Preferred stock, ending balance at Mar. 31, 2018			$ 12
Common stock, shares outstanding, ending balance (in shares) at Mar. 31, 2018				3,056
Common stock, ending balance at Mar. 31, 2018	$ 64,585			$ 2	180,093	231	(115,753)
Preferred stock, shares outstanding, beginning balance (in shares) at Dec. 31, 2018	0	0
Preferred stock, beginning balance at Dec. 31, 2018		$ 0
Common stock, shares outstanding, beginning balance (in shares) at Dec. 31, 2018	36,705			36,705
Common stock, beginning balance at Dec. 31, 2018	$ 217,783			$ 15	324,656	(2,157)	(104,731)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	$ (1,235)						(1,235)
Exercise of stock options (in shares)	201			201
Exercise of stock options	$ 466				466
Stock-based compensation	1,909				1,748		161
Cumulative translation adjustment	$ (260)					(260)
Preferred stock, shares outstanding, ending balance (in shares) at Mar. 31, 2019	0	0
Preferred stock, ending balance at Mar. 31, 2019		$ 0
Common stock, shares outstanding, ending balance (in shares) at Mar. 31, 2019	36,906			36,906
Common stock, ending balance at Mar. 31, 2019	$ 218,663			$ 15	$ 326,870	$ (2,417)	$ (105,805)

Organization and Operations of

Organization and Operations of the Company	3 Months Ended
	Mar. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Operations of the Company	Organization and Operations of the Company nLIGHT, Inc. (the "Company") is a leading provider of high-power semiconductor and fiber lasers used in a variety of end applications in the industrial, microfabrication, and aerospace and defense markets. The Company, a Delaware corporation, is headquartered in Vancouver, Washington and is vertically integrated with manufacturing in Vancouver, Washington; Hillsboro, Oregon; Shanghai, China; and Lohja, Finland.

Summary of Significant Accounti

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2019
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies (a) Principles of Consolidation and Presentation The accompanying consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America ("U.S. GAAP") and relate to nLIGHT, Inc. and its wholly owned subsidiaries. Certain information and footnote disclosures normally included in financial statements prepared in accordance with U.S. GAAP have been condensed or omitted pursuant to the rules and regulations of the Securities and Exchange Commission ("SEC"). All intercompany balances have been eliminated. In the opinion of the Company's management, the unaudited financial information for the interim periods presented reflects all adjustments necessary for a fair presentation of the Company's financial position, results of operations and cash flows. The results reported in these consolidated financial statements are not necessarily indicative of results that may be expected for the full year. These consolidated financial statements should be read in conjunction with the consolidated financial statements and notes thereto for the year ended December 31, 2018 . We have reclassified certain amounts in prior-periods financial statements to conform to the current period's presentation. On the consolidated balance sheets we present accumulated depreciation and amortization. On the cash flow statements we present depreciation and amortization as separate adjustments to reconcile net income (loss) to net cash used in operating activities. (b) Use of Estimates The preparation of consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. On an ongoing basis, the Company evaluates its estimates, including those related to inventory valuation, allowances for doubtful accounts, warranty, sales return reserves and the recoverability of long-lived assets. Management of the Company bases its estimates on historical experience and on various other assumptions. Actual results could differ from those estimates. (c) Revenue Recognition See Note 3, Revenue . (d) Risks and Uncertainties including Business and Credit Concentrations The following customers accounted for 10% or more of our revenues for the periods presented: Three Months Ended March 31, 2019 2018 Raytheon Company 11.1% — Suzhou Quick Laser Technology Co., Ltd. — 12.7% Financial instruments that potentially expose the Company to concentrations of credit risk consist principally of accounts receivable. As of March 31, 2019 , two customers accounted for 20.2% and 11.2% of gross accounts receivable, respectively. As of December 31, 2018 , one customer accounted for 16.6% of gross accounts receivable. No other customers accounted for 10% or more of gross accounts receivable in either of these periods. (e) Property and Equipment Property and equipment are stated at cost. Improvements and replacements are capitalized. Repair and maintenance costs are expensed as incurred. Depreciation is computed using the straight‑line method over the estimated useful life of each asset, generally two to 12 years . (f) Stock‑Based Compensation Stock‑based compensation is recognized at the grant date fair value and is recognized as expense over the requisite service period. The Company recognizes stock-based compensation for all time-based awards on a straight-line basis. Expense for performance-based awards is recognized over the requisite service period based on the probability of achievement of the performance criteria. The Company's time-based awards consist of stock options, restricted stock units, and restricted stock awards. Performance-based awards consist of restricted stock units and restricted stock awards. Total stock-based compensation expense by financial statement caption was as follows: Three Months Ended March 31, 2019 2018 Cost of revenues $ 209 $ 22 Research and development 558 25 Sales, general and administrative 1,142 115 $ 1,909 $ 162 (g) Commitments and Contingencies Liabilities for loss contingencies are recorded when it is probable that a liability has been incurred and the amount of the loss can be reasonably estimated. The Company becomes involved in various legal proceedings and claims incidental to normal business activities. As of March 31, 2019 , the Company believes these matters will not have a material adverse effect on the consolidated financial statements. There have been no material changes to the commitments and contingencies as previously disclosed in the Company's annual report for the year ended December 31, 2018 . (h) Fair Value of Financial Instruments The Company's fair value hierarchy for its financial instruments consists of cash equivalents as follows: March 31, 2019 Level 1 Level 2 Level 3 Total Money market securities $ 123,815 $ — $ — $ 123,815 Commercial paper 41 — — 41 Total $ 123,856 $ — $ — $ 123,856 December 31, 2018 Level 1 Level 2 Level 3 Total Money market securities $ 123,121 $ — $ — $ 123,121 Commercial paper 299 — — 299 Total $ 123,420 $ — $ — $ 123,420 There have been no other material changes to the financial instruments as previously disclosed in the Company's annual report for the year ended December 31, 2018 . (i) Recently Issued Accounting Standards Newly-Adopted Standards The Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") No. 2018-07, Improvements to Nonemployee Share-Based Payment Accounting (Topic 718) , in June 2018. ASU 2018-07 simplifies the accounting for share-based payments made to nonemployees so the accounting for such payments is substantially the same as those made to employees. The Company adopted ASU 2018-07 on January 1, 2019 using the modified retrospective approach with fair value measurement of unsettled liability-classified nonemployee awards, and recorded a cumulative effect adjustment of $161 thousand to beginning retained earnings. Issued Not Yet Adopted Standards The FASB issued ASU No. 2016‑02, Leases (Topic 842) , in February 2016. ASU 2016‑02 requires a lessee to recognize a right of use asset and a lease liability for virtually all leases, other than leases that meet the definition of short‑term. ASU 2016-02, as amended, is effective for annual reporting periods of emerging growth companies beginning after December 15, 2019. The Company expects to implement the provisions of ASU 2016‑02, as amended, as of January 1, 2020. The Company is currently evaluating the impact of this ASU, as amended, and cannot reasonably estimate the quantitative impact on the financial statements at this time. However, the Company does expect the most significant effects to relate to the recognition of new right-of-use ("ROU") assets and lease liabilities on its balance sheet for the Company's facilities operating leases. In addition, the Company expects this ASU, as amended, to have significant additional disclosure requirements.

Revenue

Revenue	3 Months Ended
	Mar. 31, 2019
Revenue from Contract with Customer [Abstract]
Revenue	Revenue (a) Adoption of ASC 606 The Company adopted ASC 606 “ Revenue from Contracts with Customers” using the cumulative effect method with a date of initial application of January 1, 2019. Therefore, the comparative period information has not been adjusted and continues to be reported under ASC 605 “ Revenue Recognition. ” The impact of adoption was immaterial, and the Company expects the impact of the adoption of the new standard to be immaterial to the consolidated financial statements on an ongoing basis. A majority of the Company's revenue continues to be recognized at a point in time when control transfers based on the terms of the underlying contract. (b) Revenue Recognition Revenue is recognized when transfer of control to the customer occurs in an amount reflecting the consideration to which the Company expects to be entitled. In order to achieve this core principle, the Company applies the following five step approach: (1) identify the contract with a customer, (2) identify the performance obligations in the contract, (3) determine the transaction price, (4) allocate the transaction price to the performance obligations in the contract, and (5) recognize revenue when a performance obligation is satisfied. The Company considers customer purchase orders, which in some cases are governed by master sales agreements, to be the contracts with a customer. As part of its consideration of the contract, the Company evaluates certain factors including the customer's ability to pay (or credit risk). For each contract, the Company considers the promise to transfer products, each of which is distinct, as the identified performance obligations. As the Company's standard payment terms are less than one year, the Company has elected the practical expedient under ASC 606-10-32-18 to not assess whether a contract has a significant financing component. Payment terms in excess of one year are evaluated as they occur. The Company allocates the transaction price to each distinct product based on its relative standalone selling price. Master sales agreements or purchase orders from customers could include a single product or multiple products. Regardless, the contracted price with the customer is agreed to at the individual product level outlined in the customer contract or purchase order. The Company does not bundle prices; however, it does negotiate with customers on pricing for the same products based on a variety of factors (e.g. level of contractual volume). The Company has concluded that the prices negotiated with each individual customer are representative of the stand-alone selling price of the product. Revenue is recognized when control of the product is transferred to the customer (i.e., when the Company's performance obligation is satisfied), which typically occurs at shipment or delivery, depending on shipping terms. The Company often receives orders with multiple delivery dates that may extend across several reporting periods. The Company allocates the transaction price of the contract to each delivery based on the product standalone selling price. The Company invoices for each scheduled delivery upon shipment or delivery and recognizes revenues for such delivery at that point, assuming transfer of control has occurred. As scheduled delivery dates are generally within one year, under the optional exemption provided by ASC 606-10-50-14 revenues allocated to future shipments of partially completed contracts are not disclosed. Rights of return generally are not included in customer contracts. Accordingly, product revenue is recognized upon shipment or delivery, as applicable, and transfer of control. Rights of return are evaluated as they occur. As part of its adoption of the new revenue standard, the Company has elected to account for shipping and handling as fulfillment activities and record them in cost of sales. The election of this practical expedient results in accounting treatment consistent with the Company’s historical accounting policies and therefore, this election does not impact the comparability of the financial statements. Revenue Recognition at a Point in Time - Revenues recognized at a point in time consist of sales of semiconductor lasers, fiber lasers and other related products. Revenue Recognition over Time - Revenues recognized over time generally consist of arrangements for goods and services that are structured based on the Company’s costs. Revenue for these arrangements is recognized as control transfers, which occurs as the work is performed. Billing under these arrangements generally occurs within one month after the work is completed. The following tables represent a disaggregation of revenue from contracts with customers for the period presented: Sales by End Market Three Months Ended March 31, 2019 (in thousands) Industrial $ 18,124 Microfabrication 14,533 Aerospace and Defense 9,204 $ 41,861 Sales by Geography Three Months Ended March 31, 2019 (in thousands) North America $ 15,770 China 13,653 Rest of World 12,438 $ 41,861 The Company frequently receives consideration from a customer prior to transferring goods to the customer under the terms of a sales contract. The Company records customer deposits related to these prepayments, which represent contract liabilities. The Company also records deferred revenue related to products for which consideration is received before the performance obligation has been satisfied. The Company recognizes customer deposits and deferred revenue as revenues after control of the goods or services has been transferred to the customer and the corresponding performance obligations are satisfied. These amounts are reflected within the balance sheet under customer advances and deferred revenue. During the three months ended March 31, 2019 , the Company recognized revenue of $0.7 million that was included in the customer advances and deferred revenue balances at the beginning of the period as the performance obligations under the associated agreements were satisfied during the three months ended March 31, 2019 .

Prepaid Expenses and Other Curr

Prepaid Expenses and Other Current Assets	3 Months Ended
	Mar. 31, 2019
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Prepaid Expenses and Other Current Assets	Prepaid Expenses and Other Current Assets The components of prepaid expenses and other current assets are as follows: March 31, December 31, (in thousands) 2019 2018 Prepaid expenses $ 2,281 $ 1,654 Value-added tax receivable, net 795 1,489 Vendor prepayments 196 1,263 Prepaid tax and duties 2,491 2,777 Other 59 103 $ 5,822 $ 7,286

Inventory

Inventory	3 Months Ended
	Mar. 31, 2019
Inventory Disclosure [Abstract]
Inventory	Inventory Inventory is stated at the lower of average cost and net realizable value. The components of inventory are as follows: March 31, December 31, (in thousands) 2019 2018 Raw materials $ 16,044 $ 14,174 Work in process and semi-finished goods 14,590 12,807 Finished goods 10,212 8,348 $ 40,846 $ 35,329

Goodwill

Goodwill	3 Months Ended
	Mar. 31, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill	Goodwill There were no changes in the carrying amount of goodwill during the three months ended March 31, 2019 and 2018 .

Other Assets

Other Assets	3 Months Ended
	Mar. 31, 2019
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Other Assets	Other Assets Other assets consisted of the following: March 31, December 31, (in thousands) 2019 2018 Demonstration assets, net $ 2,069 $ 1,982 Deferred tax assets, net 3,114 3,114 Other 846 878 $ 6,029 $ 5,974 Demonstration (demo) assets are equipment that is used for demonstration and other purposes with existing and prospective customers. Demo assets are recorded at cost and amortized over an estimated useful life of approximately two years . Amortization expense for demo assets totaled $0.5 million and $0.4 million for the three months ended March 31, 2019 and 2018 , respectively.

Accrued Liabilities

Accrued Liabilities	3 Months Ended
	Mar. 31, 2019
Payables and Accruals [Abstract]
Accrued Liabilities	Accrued Liabilities Accrued liabilities consist of the following: March 31, December 31, (in thousands) 2019 2018 Accrued payroll and benefits $ 5,565 $ 6,474 Product warranty, current 2,168 2,669 Income tax payable 447 258 Other accrued expenses 1,651 1,307 $ 9,831 $ 10,708

Product Warranties

Product Warranties	3 Months Ended
	Mar. 31, 2019
Guarantees and Product Warranties [Abstract]
Product Warranties	Product Warranties The Company's products are sold with warranty provisions that require the Company to remedy deficiencies in quality or performance over a specified period of time, generally four to 36 months , and occasionally up to 63 months for new products, at no cost to its customers. Net warranty charges incurred include labor charges and costs of replacement parts for repairs under warranty. A provision for the estimated future costs of warranty is based upon historical cost and product performance experience, and is recorded when revenues are recognized. The warranty accrual is recorded within the accrued liabilities and other long-term liabilities captions, based on the performance period. The following is a reconciliation of the changes in the aggregate product warranty liability during the three months ended March 31, 2019 and 2018 : Three Months Ended March 31, (in thousands) 2019 2018 Product warranty liability, beginning $ 4,555 $ 4,186 Warranty charges incurred, net (433 ) (526 ) Provision for warranty charges, net of adjustments (398 ) 730 Product warranty liability, ending $ 3,724 $ 4,390 Less: current portion of product warranty liability (2,168 ) (3,495 ) Non-current portion of product warranty liability $ 1,556 $ 895

Long-Term Debt

Long-Term Debt	3 Months Ended
	Mar. 31, 2019
Debt Disclosure [Abstract]
Long-Term Debt	Long‑Term Debt The terms of the Company's long-term debt arrangements were reported in its annual report for the year ended December 31, 2018 . There have been no material changes to those arrangements during the three months ended March 31, 2019 . The term loan and revolving loan balances were zero at March 31, 2019 and December 31, 2018 , respectively, and the Company was in compliance with all of its financial covenants as of those dates. Long‑term debt consists of the following: March 31, December 31, (in thousands) 2019 2018 2014 Finland equipment loans, Danske Bank 31 41 Capital leases, various 90 110 Total debt 121 151 Less: debt issuance costs — (42 ) Total long-term debt 121 109 Less: current portion of long-term debt (102 ) (91 ) Non-current portion of long-term debt $ 19 $ 18

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2019
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes Income Tax Provision To calculate the interim tax provision, at the end of each interim period the Company estimates the annual effective tax rate and applies that to its ordinary quarterly earnings. The effect of changes in the enacted tax laws or rates is recognized in the interim period in which the change occurs. The computation of the annual estimated effective tax rate at each interim period requires certain estimates and judgments including, but not limited to, the expected operating income for the year, projections of the proportion of income earned and taxed in foreign jurisdictions, permanent differences between book and tax amounts, and the likelihood of recovering deferred tax assets generated in the current year. The accounting estimates used to compute the provision for income taxes may change as new events occur, additional information is obtained, or the tax environment changes. The Company’s effective tax rate for the three months ended March 31, 2019 and 2018 differs from the U.S. statutory rate due to the U.S. valuation allowance, foreign income taxed at local statutory rates, and accrued withholding taxes. The increase in the effective tax rate from 2018 to 2019 is primarily due to decreased profitability within the U.S. entity as the Company maintains a full valuation allowance against the U.S. deferred tax assets. In fiscal year to date 2019 , the Company reported U.S. pre-tax losses, consistent with prior fiscal years to date within this decade, other than 2018. The Company has not yet been able to establish a sustained level of profitability in the U.S. or other sufficient significant positive evidence to conclude that its U.S. deferred tax assets are more likely than not to be realized. Therefore, the Company continues to maintain a valuation allowance against its U.S. deferred tax assets. It is reasonably possible that by the end of 2019 , the Company will establish a sustained level of profitability in the U.S. As a result, it may reverse a significant portion of the valuation allowance recorded against its U.S. deferred tax assets. The reversal would result in an income tax benefit for the three months and the year ending December 31, 2019 .

Stockholders' Equity

Stockholders' Equity	3 Months Ended
	Mar. 31, 2019
Equity [Abstract]
Stockholders' Equity	Stockholders’ Equity (a) 2018 Equity Incentive Plan and 2018 Employee Stock Purchase Plan For the three months ended March 31, 2019 , there were no material changes to the Company's 2018 Equity Incentive Plan and the 2018 Employee Stock Purchase Plan from our annual report for the year ended December 31, 2018 . (b) 2001 Stock Option Plan The following table summarizes the Company’s stock option activity during the three months ended March 31, 2019 : (in thousands, except weighted average prices) Number of shares Weighted average exercise price Weighted average remaining contractual term (years) Aggregate intrinsic value Outstanding, December 31, 2018 5,171 $1.60 7.2 $83,700 Options exercised (201 ) $2.33 Options canceled (14 ) $2.87 Outstanding, March 31, 2019 4,956 $1.56 6.8 $102,681 Options exercisable at March 31, 2019 3,102 $1.00 6.2 $65,998 Options vested as of March 31, 2019 and expected to vest after March 31, 2019 4,956 $1.56 6.8 $102,681 Total intrinsic value of options exercised for the three months ended March 31, 2019 and 2018 was $3.6 million and $678 thousand , respectively. The Company received proceeds of $467 thousand and $61 thousand from the exercise of options for the three months ended March 31, 2019 and 2018 , respectively.

Net Income (Loss) per Share

Net Income (Loss) per Share	3 Months Ended
	Mar. 31, 2019
Earnings Per Share [Abstract]
Net Income (Loss) per Share	Net Income (Loss) per Share Net income (loss) per share is presented in conformity with the two‑class method required for multiple classes of common stock and participating securities. The participating securities include convertible preferred stock as the holders of these securities are entitled to receive a noncumulative dividend in preference to the common stockholders in the event that a dividend is declared on common stock. The convertible preferred stock converted to common stock on April 30, 2018 upon the closing of the Company's initial public offering. As such, for the three months ended March 31, 2018 , income earned has been allocated to these participating securities. Basic income per share is computed using the weighted average number of common shares outstanding during the period, and excludes any dilutive effects of common stock equivalent shares such as stock options, restricted stock, warrants, and convertible preferred stock. Diluted income per share is computed using the weighted average number of common shares outstanding and potentially dilutive common stock options, restricted stock, warrants, and convertible preferred stock. The following table sets forth the calculation of basic and diluted net income (loss) per share attributable to common stockholders during the periods presented: Three Months Ended March 31, (in thousands, except per share data) 2019 2018 Numerator: Net income (loss) $ (1,235 ) $ 2,916 Participating securities: Income allocated to participating securities — (2,916 ) Net income (loss) attributable to common stockholders (1,235 ) — Denominator: Weighted-average shares, basic 36,694 3,031 Weighted-average common shares outstanding, diluted 36,694 3,031 Net income (loss) per share attributable to common stockholders: Basic $ (0.03 ) $ — Diluted $ (0.03 ) $ — The following potentially dilutive shares of convertible preferred stock, preferred stock warrants, restricted stock awards and units, and stock options were not included in the calculation of diluted shares above as the effect would have been anti‑dilutive: Three Months Ended March 31, (in thousands) 2019 2018 Convertible preferred stock — 24,642 Preferred stock warrants — 214 Restricted stock units and awards 681 — Employee stock purchase plan 44 — Common stock options 4,956 5,630 Total 5,681 30,486

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2019
Accounting Policies [Abstract]
Principles of Consolidation and Presentation	Principles of Consolidation and Presentation The accompanying consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America ("U.S. GAAP") and relate to nLIGHT, Inc. and its wholly owned subsidiaries. Certain information and footnote disclosures normally included in financial statements prepared in accordance with U.S. GAAP have been condensed or omitted pursuant to the rules and regulations of the Securities and Exchange Commission ("SEC"). All intercompany balances have been eliminated. In the opinion of the Company's management, the unaudited financial information for the interim periods presented reflects all adjustments necessary for a fair presentation of the Company's financial position, results of operations and cash flows. The results reported in these consolidated financial statements are not necessarily indicative of results that may be expected for the full year. These consolidated financial statements should be read in conjunction with the consolidated financial statements and notes thereto for the year ended December 31, 2018 . We have reclassified certain amounts in prior-periods financial statements to conform to the current period's presentation. On the consolidated balance sheets we present accumulated depreciation and amortization. On the cash flow statements we present depreciation and amortization as separate adjustments to reconcile net income (loss) to net cash used in operating activities.
Use of Estimates	Use of Estimates The preparation of consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. On an ongoing basis, the Company evaluates its estimates, including those related to inventory valuation, allowances for doubtful accounts, warranty, sales return reserves and the recoverability of long-lived assets. Management of the Company bases its estimates on historical experience and on various other assumptions. Actual results could differ from those estimates.
Property and Equipment	Property and Equipment Property and equipment are stated at cost. Improvements and replacements are capitalized. Repair and maintenance costs are expensed as incurred. Depreciation is computed using the straight‑line method over the estimated useful life of each asset, generally two to 12 years .
Stock‑Based Compensation	Stock‑Based Compensation Stock‑based compensation is recognized at the grant date fair value and is recognized as expense over the requisite service period. The Company recognizes stock-based compensation for all time-based awards on a straight-line basis. Expense for performance-based awards is recognized over the requisite service period based on the probability of achievement of the performance criteria. The Company's time-based awards consist of stock options, restricted stock units, and restricted stock awards. Performance-based awards consist of restricted stock units and restricted stock awards.
Commitments and Contingencies	Commitments and Contingencies Liabilities for loss contingencies are recorded when it is probable that a liability has been incurred and the amount of the loss can be reasonably estimated. The Company becomes involved in various legal proceedings and claims incidental to normal business activities.
Recently Issued Accounting Standards	Recently Issued Accounting Standards Newly-Adopted Standards The Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") No. 2018-07, Improvements to Nonemployee Share-Based Payment Accounting (Topic 718) , in June 2018. ASU 2018-07 simplifies the accounting for share-based payments made to nonemployees so the accounting for such payments is substantially the same as those made to employees. The Company adopted ASU 2018-07 on January 1, 2019 using the modified retrospective approach with fair value measurement of unsettled liability-classified nonemployee awards, and recorded a cumulative effect adjustment of $161 thousand to beginning retained earnings. Issued Not Yet Adopted Standards The FASB issued ASU No. 2016‑02, Leases (Topic 842) , in February 2016. ASU 2016‑02 requires a lessee to recognize a right of use asset and a lease liability for virtually all leases, other than leases that meet the definition of short‑term. ASU 2016-02, as amended, is effective for annual reporting periods of emerging growth companies beginning after December 15, 2019. The Company expects to implement the provisions of ASU 2016‑02, as amended, as of January 1, 2020. The Company is currently evaluating the impact of this ASU, as amended, and cannot reasonably estimate the quantitative impact on the financial statements at this time. However, the Company does expect the most significant effects to relate to the recognition of new right-of-use ("ROU") assets and lease liabilities on its balance sheet for the Company's facilities operating leases. In addition, the Company expects this ASU, as amended, to have significant additional disclosure requirements.
Revenue Recognition	Revenue Recognition Revenue is recognized when transfer of control to the customer occurs in an amount reflecting the consideration to which the Company expects to be entitled. In order to achieve this core principle, the Company applies the following five step approach: (1) identify the contract with a customer, (2) identify the performance obligations in the contract, (3) determine the transaction price, (4) allocate the transaction price to the performance obligations in the contract, and (5) recognize revenue when a performance obligation is satisfied. The Company considers customer purchase orders, which in some cases are governed by master sales agreements, to be the contracts with a customer. As part of its consideration of the contract, the Company evaluates certain factors including the customer's ability to pay (or credit risk). For each contract, the Company considers the promise to transfer products, each of which is distinct, as the identified performance obligations. As the Company's standard payment terms are less than one year, the Company has elected the practical expedient under ASC 606-10-32-18 to not assess whether a contract has a significant financing component. Payment terms in excess of one year are evaluated as they occur. The Company allocates the transaction price to each distinct product based on its relative standalone selling price. Master sales agreements or purchase orders from customers could include a single product or multiple products. Regardless, the contracted price with the customer is agreed to at the individual product level outlined in the customer contract or purchase order. The Company does not bundle prices; however, it does negotiate with customers on pricing for the same products based on a variety of factors (e.g. level of contractual volume). The Company has concluded that the prices negotiated with each individual customer are representative of the stand-alone selling price of the product. Revenue is recognized when control of the product is transferred to the customer (i.e., when the Company's performance obligation is satisfied), which typically occurs at shipment or delivery, depending on shipping terms. The Company often receives orders with multiple delivery dates that may extend across several reporting periods. The Company allocates the transaction price of the contract to each delivery based on the product standalone selling price. The Company invoices for each scheduled delivery upon shipment or delivery and recognizes revenues for such delivery at that point, assuming transfer of control has occurred. As scheduled delivery dates are generally within one year, under the optional exemption provided by ASC 606-10-50-14 revenues allocated to future shipments of partially completed contracts are not disclosed. Rights of return generally are not included in customer contracts. Accordingly, product revenue is recognized upon shipment or delivery, as applicable, and transfer of control. Rights of return are evaluated as they occur. As part of its adoption of the new revenue standard, the Company has elected to account for shipping and handling as fulfillment activities and record them in cost of sales. The election of this practical expedient results in accounting treatment consistent with the Company’s historical accounting policies and therefore, this election does not impact the comparability of the financial statements. Revenue Recognition at a Point in Time - Revenues recognized at a point in time consist of sales of semiconductor lasers, fiber lasers and other related products. Revenue Recognition over Time - Revenues recognized over time generally consist of arrangements for goods and services that are structured based on the Company’s costs. Revenue for these arrangements is recognized as control transfers, which occurs as the work is performed. Billing under these arrangements generally occurs within one month after the work is completed.
Inventory	Inventory is stated at the lower of average cost and net realizable value
Product Warranties	The Company's products are sold with warranty provisions that require the Company to remedy deficiencies in quality or performance over a specified period of time, generally four to 36 months , and occasionally up to 63 months for new products, at no cost to its customers. Net warranty charges incurred include labor charges and costs of replacement parts for repairs under warranty. A provision for the estimated future costs of warranty is based upon historical cost and product performance experience, and is recorded when revenues are recognized. The warranty accrual is recorded within the accrued liabilities and other long-term liabilities captions, based on the performance period.
Income Taxes	To calculate the interim tax provision, at the end of each interim period the Company estimates the annual effective tax rate and applies that to its ordinary quarterly earnings. The effect of changes in the enacted tax laws or rates is recognized in the interim period in which the change occurs. The computation of the annual estimated effective tax rate at each interim period requires certain estimates and judgments including, but not limited to, the expected operating income for the year, projections of the proportion of income earned and taxed in foreign jurisdictions, permanent differences between book and tax amounts, and the likelihood of recovering deferred tax assets generated in the current year. The accounting estimates used to compute the provision for income taxes may change as new events occur, additional information is obtained, or the tax environment changes.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	3 Months Ended
	Mar. 31, 2019
Accounting Policies [Abstract]
Schedule of stock-based compensation expense	Total stock-based compensation expense by financial statement caption was as follows: Three Months Ended March 31, 2019 2018 Cost of revenues $ 209 $ 22 Research and development 558 25 Sales, general and administrative 1,142 115 $ 1,909 $ 162
Schedule of fair value hierarchy for its cash equivalents	The Company's fair value hierarchy for its financial instruments consists of cash equivalents as follows: March 31, 2019 Level 1 Level 2 Level 3 Total Money market securities $ 123,815 $ — $ — $ 123,815 Commercial paper 41 — — 41 Total $ 123,856 $ — $ — $ 123,856 December 31, 2018 Level 1 Level 2 Level 3 Total Money market securities $ 123,121 $ — $ — $ 123,121 Commercial paper 299 — — 299 Total $ 123,420 $ — $ — $ 123,420

Revenue (Tables)

Revenue (Tables)	3 Months Ended
	Mar. 31, 2019
Revenue from Contract with Customer [Abstract]
Schedule of sales by end market	Sales by End Market Three Months Ended March 31, 2019 (in thousands) Industrial $ 18,124 Microfabrication 14,533 Aerospace and Defense 9,204 $ 41,861
Schedule of sales by geography	Sales by Geography Three Months Ended March 31, 2019 (in thousands) North America $ 15,770 China 13,653 Rest of World 12,438 $ 41,861

Prepaid Expenses and Other Cu_2

Prepaid Expenses and Other Current Assets (Tables)	3 Months Ended
	Mar. 31, 2019
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Scheudle of components of prepaid expenses and other current assets	The components of prepaid expenses and other current assets are as follows: March 31, December 31, (in thousands) 2019 2018 Prepaid expenses $ 2,281 $ 1,654 Value-added tax receivable, net 795 1,489 Vendor prepayments 196 1,263 Prepaid tax and duties 2,491 2,777 Other 59 103 $ 5,822 $ 7,286

Inventory (Tables)

Inventory (Tables)	3 Months Ended
	Mar. 31, 2019
Inventory Disclosure [Abstract]
Schedule of components of inventory	The components of inventory are as follows: March 31, December 31, (in thousands) 2019 2018 Raw materials $ 16,044 $ 14,174 Work in process and semi-finished goods 14,590 12,807 Finished goods 10,212 8,348 $ 40,846 $ 35,329

Other Assets (Tables)

Other Assets (Tables)	3 Months Ended
	Mar. 31, 2019
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Schedule of other assets	Other assets consisted of the following: March 31, December 31, (in thousands) 2019 2018 Demonstration assets, net $ 2,069 $ 1,982 Deferred tax assets, net 3,114 3,114 Other 846 878 $ 6,029 $ 5,974

Accrued Liabilities (Tables)

Accrued Liabilities (Tables)	3 Months Ended
	Mar. 31, 2019
Payables and Accruals [Abstract]
Summary of accrued liabilities	Accrued liabilities consist of the following: March 31, December 31, (in thousands) 2019 2018 Accrued payroll and benefits $ 5,565 $ 6,474 Product warranty, current 2,168 2,669 Income tax payable 447 258 Other accrued expenses 1,651 1,307 $ 9,831 $ 10,708

Product Warranties (Tables)

Product Warranties (Tables)	3 Months Ended
	Mar. 31, 2019
Guarantees and Product Warranties [Abstract]
Reconciliation of the changes in the aggregate product warranty liability	The following is a reconciliation of the changes in the aggregate product warranty liability during the three months ended March 31, 2019 and 2018 : Three Months Ended March 31, (in thousands) 2019 2018 Product warranty liability, beginning $ 4,555 $ 4,186 Warranty charges incurred, net (433 ) (526 ) Provision for warranty charges, net of adjustments (398 ) 730 Product warranty liability, ending $ 3,724 $ 4,390 Less: current portion of product warranty liability (2,168 ) (3,495 ) Non-current portion of product warranty liability $ 1,556 $ 895

Long-Term Debt (Tables)

Long-Term Debt (Tables)	3 Months Ended
	Mar. 31, 2019
Debt Disclosure [Abstract]
Schedule of long-term debt	Long‑term debt consists of the following: March 31, December 31, (in thousands) 2019 2018 2014 Finland equipment loans, Danske Bank 31 41 Capital leases, various 90 110 Total debt 121 151 Less: debt issuance costs — (42 ) Total long-term debt 121 109 Less: current portion of long-term debt (102 ) (91 ) Non-current portion of long-term debt $ 19 $ 18

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	3 Months Ended
	Mar. 31, 2019
Equity [Abstract]
Summary of stock option activity	The following table summarizes the Company’s stock option activity during the three months ended March 31, 2019 : (in thousands, except weighted average prices) Number of shares Weighted average exercise price Weighted average remaining contractual term (years) Aggregate intrinsic value Outstanding, December 31, 2018 5,171 $1.60 7.2 $83,700 Options exercised (201 ) $2.33 Options canceled (14 ) $2.87 Outstanding, March 31, 2019 4,956 $1.56 6.8 $102,681 Options exercisable at March 31, 2019 3,102 $1.00 6.2 $65,998 Options vested as of March 31, 2019 and expected to vest after March 31, 2019 4,956 $1.56 6.8 $102,681

Net Income (Loss) per Share (Ta

Net Income (Loss) per Share (Tables)	3 Months Ended
	Mar. 31, 2019
Earnings Per Share [Abstract]
Schedule of basic and diluted net income (loss) per share	The following table sets forth the calculation of basic and diluted net income (loss) per share attributable to common stockholders during the periods presented: Three Months Ended March 31, (in thousands, except per share data) 2019 2018 Numerator: Net income (loss) $ (1,235 ) $ 2,916 Participating securities: Income allocated to participating securities — (2,916 ) Net income (loss) attributable to common stockholders (1,235 ) — Denominator: Weighted-average shares, basic 36,694 3,031 Weighted-average common shares outstanding, diluted 36,694 3,031 Net income (loss) per share attributable to common stockholders: Basic $ (0.03 ) $ — Diluted $ (0.03 ) $ —
Schedule of potentially dilutive shares not included in calculation of diluted shares	The following potentially dilutive shares of convertible preferred stock, preferred stock warrants, restricted stock awards and units, and stock options were not included in the calculation of diluted shares above as the effect would have been anti‑dilutive: Three Months Ended March 31, (in thousands) 2019 2018 Convertible preferred stock — 24,642 Preferred stock warrants — 214 Restricted stock units and awards 681 — Employee stock purchase plan 44 — Common stock options 4,956 5,630 Total 5,681 30,486

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Risks and Uncertainties Including Business and Credit Concentrations (Details) - Customer concentration risk	3 Months Ended		12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Raytheon Company | Sales revenue
Product Information [Line Items]
Concentration risk, percentage	11.10%
Suzhou Quick Laser Technology Co., Ltd. | Sales revenue
Product Information [Line Items]
Concentration risk, percentage		12.70%
Two customers, one | Accounts receivable
Product Information [Line Items]
Concentration risk, percentage	20.20%
Two customers, two | Accounts receivable
Product Information [Line Items]
Concentration risk, percentage	11.20%
One customer | Accounts receivable
Product Information [Line Items]
Concentration risk, percentage			17.00%

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Property and Equipment (Details)	3 Months Ended
	Mar. 31, 2019
Minimum
Property, Plant and Equipment [Line Items]
Property and equipment useful life	2 years
Maximum
Property, Plant and Equipment [Line Items]
Property and equipment useful life	12 years

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Stock-Based Compensation - Expense by Financial Statement Caption (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	$ 1,909	$ 162	$ 308
Cost of revenues
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	209	22	30
Research and development
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	558	25	57
Sales, general and administrative
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	$ 1,142	$ 115	$ 221

Summary of Significant Accoun_7

Summary of Significant Accounting Policies - Fair Value Hierarchy for Cash and Cash Equivalents (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents, fair value	$ 123,856	$ 123,420
Money market securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents, fair value	123,815	123,121
Commercial paper
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents, fair value	41	299
Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents, fair value	123,856	123,420
Level 1 | Money market securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents, fair value	123,815	123,121
Level 1 | Commercial paper
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents, fair value	41	299
Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents, fair value	0	0
Level 2 | Money market securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents, fair value	0	0
Level 2 | Commercial paper
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents, fair value	0	0
Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents, fair value	0	0
Level 3 | Money market securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents, fair value	0	0
Level 3 | Commercial paper
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents, fair value	$ 0	$ 0

Summary of Significant Accoun_8

Summary of Significant Accounting Policies - Recently Issued Accounting Standards (Details) $ in Thousands	Jan. 01, 2019USD ($)
Retained earnings | Accounting Standards Update 2018-07
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect adjustment	$ 161

Revenue - Disaggregation of Rev

Revenue - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Disaggregation of Revenue [Line Items]
Revenues	$ 41,861	$ 42,467
North America
Disaggregation of Revenue [Line Items]
Revenues	15,770
China
Disaggregation of Revenue [Line Items]
Revenues	13,653
Rest of World
Disaggregation of Revenue [Line Items]
Revenues	12,438
Industrial
Disaggregation of Revenue [Line Items]
Revenues	18,124
Microfabrication
Disaggregation of Revenue [Line Items]
Revenues	14,533
Aerospace and Defense
Disaggregation of Revenue [Line Items]
Revenues	$ 9,204

Revenue - Narrative (Details)

Revenue - Narrative (Details) $ in Millions	3 Months Ended
	Mar. 31, 2019USD ($)
Revenue from Contract with Customer [Abstract]
Revenue recognized, previously included in customer advances and deferred revenue	$ 0.7

Prepaid Expenses and Other Cu_3

Prepaid Expenses and Other Current Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Prepaid Expense and Other Assets, Current [Abstract]
Prepaid expenses	$ 2,281	$ 1,654
Value-added tax receivable, net	795	1,489
Vendor prepayments	196	1,263
Prepaid tax and duties	2,491	2,777
Other	59	103
Prepaid expenses and other current assets	$ 5,822	$ 7,286

Inventory (Details)

Inventory (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Inventory Disclosure [Abstract]
Raw materials	$ 16,044	$ 14,174
Work in process and semi-finished goods	14,590	12,807
Finished goods	10,212	8,348
Inventory	$ 40,846	$ 35,329

Other Assets (Details)

Other Assets (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Other Assets, Noncurrent Disclosure [Abstract]
Demonstration assets, net	$ 2,069		$ 1,982
Deferred tax assets, net	3,114		3,114
Other	846		878
Other assets	$ 6,029		$ 5,974
Useful life of demonstration assets	2 years
Amortization expense for demonstration assets	$ 500	$ 400

Accrued Liabilities (Details)

Accrued Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Payables and Accruals [Abstract]
Accrued payroll and benefits	$ 5,565	$ 6,474
Product warranty, current	2,168	2,669
Income tax payable	447	258
Other accrued expenses	1,651	1,307
Total accrued liabilities	$ 9,831	$ 10,708

Product Warranties (Details)

Product Warranties (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Product Warranty Liability [Line Items]
New products warranty period	63 months
Movement in Standard Product Warranty Accrual [Roll Forward]
Product warranty liability, beginning	$ 4,555	$ 4,186
Warranty charges incurred, net	(433)	(526)
Provision for warranty charges, net of adjustments	(398)	730
Product warranty liability, ending	3,724	4,390
Less: current portion of product warranty liability	(2,168)	(3,495)
Non-current portion of product warranty liability	$ 1,556	$ 895
Minimum
Product Warranty Liability [Line Items]
Product warranty period	4 months
Maximum
Product Warranty Liability [Line Items]
Product warranty period	36 months

Long-Term Debt - Narrative (Det

Long-Term Debt - Narrative (Details) - USD ($)	Mar. 31, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Outstanding balance	$ 121,000	$ 109,000
Term Loan
Debt Instrument [Line Items]
Outstanding balance	$ 0	$ 0

Long-Term Debt - Schedule of Lo

Long-Term Debt - Schedule of Long-term Debt (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Total debt	$ 121	$ 151
Less: debt issuance costs	0	(42)
Total long-term debt	121	109
Less: current portion of long-term debt	(102)	(91)
Non-current portion of long-term debt	19	18
Capital lease
Debt Instrument [Line Items]
Total debt	90	110
2014 Finland equipment loans, Danske Bank | Equipment Loans
Debt Instrument [Line Items]
Total debt	$ 31	$ 41

Stockholders' Equity - Summary

Stockholders' Equity - Summary of Stock Option Activity (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Number of shares
Outstanding, beginning of period (in shares)	5,171
Options exercised (in shares)	(201)
Options canceled (in shares)	(14)
Outstanding, end of period (in shares)	4,956	5,171
Weighted average exercise price
Outstanding, beginning of period (in dollars per share)	$ 1.60
Options exercised (in dollars per share)	2.33
Options canceled (in dollars per share)	2.87
Outstanding, end of period (in dollars per share)	$ 1.56	$ 1.60
Outstanding, Weighted average remaining contractual term (years)	6 years 9 months 22 days	7 years 2 months 12 days
Outstanding, Aggregate intrinsic value	$ 102,681	$ 83,700
Options exercisable at end of period
Number of shares	3,102
Weighted average exercise price (in dollars per share)	$ 1
Weighted average remaining contractual term (years)	6 years 2 months 27 days
Aggregate intrinsic value	$ 65,998
Options vested as of end of period and expected to vest after end of period
Number of shares	4,956
Weighted average exercise price (in dollars per share)	$ 1.56
Weighted average remaining contractual term (years)	6 years 9 months 22 days
Aggregate intrinsic value	$ 102,681

Stockholders' Equity - Narrativ

Stockholders' Equity - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Equity [Abstract]
Intrinsic value of options exercised	$ 3,600	$ 678
Proceeds from the exercise of options	$ 467	$ 61

Net Income (Loss) per Share - C

Net Income (Loss) per Share - Calculation of Basic and Diluted Net Income (Loss) per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Numerator:
Net income (loss)	$ (1,235)	$ 2,916
Income allocated to participating securities	0	(2,916)
Net income (loss) attributable to common stockholders	$ (1,235)	$ 0
Denominator:
Weighted-average shares, basic (in shares)	36,694	3,031
Weighted-average common shares outstanding, diluted (in shares)	36,694	3,031
Net income (loss) per share attributable to common stockholders:
Basic (in dollars per share)	$ (0.03)	$ 0
Diluted (in dollars per share)	$ (0.03)	$ 0

Net Income (Loss) per Share - A

Net Income (Loss) per Share - Antidilutive Securities Excluded from Dilutive Shares (Details) - shares shares in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities (in shares)	5,681	30,486
Convertible preferred stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities (in shares)	0	24,642
Preferred stock warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities (in shares)	0	214
Restricted stock units and awards
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities (in shares)	681	0
Employee stock purchase plan
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities (in shares)	44	0
Common stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities (in shares)	4,956	5,630