Fulgent Genetics (FLGT) 10-Q 8 Nov 19 2019 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2019	Nov. 01, 2019
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q3
Trading Symbol	FLGT
Entity Registrant Name	Fulgent Genetics, Inc.
Entity Central Index Key	0001674930
Entity Current Reporting Status	Yes
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	true
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		18,710,357
Entity File Number	001-37894
Entity Tax Identification Number	81-2621304
Entity Address, Address Line One	4978 Santa Anita Avenue
Entity Address, Address Line Two	Suite 205
Entity Address, City or Town	Temple City
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	91780
City Area Code	626
Local Phone Number	350-0537
Title of 12(b) Security	Common Stock, par value $0.0001 per share
Security Exchange Name	NASDAQ
Entity Interactive Data Current	Yes
Document Quarterly Report	true
Document Transition Report	false
Entity Incorporation, State or Country Code	DE

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Current assets
Cash and cash equivalents	$ 20,522	$ 6,736
Marketable securities	11,596	24,298
Trade accounts receivable, net of allowance for doubtful accounts of $611 and $590, as of September 30, 2019 and December 31, 2018, respectively	5,292	5,948
Other current assets	1,795	2,561
Total current assets	39,205	39,543
Marketable securities, long-term	11,487	6,386
Equity method investments	909	1,512
Fixed assets, net	6,396	6,446
Operating lease right-of-use asset	2,739
Other long-term assets	409	17
Total assets	61,145	53,904
Current liabilities
Accounts payable	2,150	1,313
Accrued liabilities	1,634	1,425
Income tax payable	60
Operating lease liabilities, short-term	409
Total current liabilities	4,253	2,738
Operating lease liabilities, long-term	2,366
Other long-term liabilities		14
Total liabilities	6,619	2,752
Commitments and contingencies (Note 8)
Stockholders’ equity
Common stock, $0.0001 par value per share, 50,000 shares authorized, 18,673 and 18,172 shares issued and outstanding at September 30, 2019 and December 31, 2018, respectively	2	2
Preferred stock, $0.0001 par value per share, 1,000 shares authorized, no shares issued or outstanding at September 30, 2019 and December 31, 2018
Additional paid-in capital	117,478	114,203
Accumulated other comprehensive income (loss)	179	(35)
Accumulated deficit	(63,133)	(63,018)
Total stockholders’ equity	54,526	51,152
Total liabilities and stockholders’ equity	$ 61,145	$ 53,904

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Statement Of Financial Position [Abstract]
Allowance for doubtful accounts receivable	$ 611	$ 590
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	50,000,000	50,000,000
Common stock, shares issued	18,673,000	18,172,000
Common stock, shares outstanding	18,673,000	18,172,000
Preferred stock, par value	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	1,000,000	1,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations (unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Income Statement [Abstract]
Revenue	$ 10,347	$ 5,625	$ 24,141	$ 15,678
Cost of revenue	3,885	2,612	10,473	7,928
Gross profit	6,462	3,013	13,668	7,750
Operating expenses:
Research and development	1,744	1,438	4,742	4,108
Selling and marketing	1,687	1,115	4,263	3,524
General and administrative	1,522	1,306	4,682	4,159
Total operating expenses	4,953	3,859	13,687	11,791
Operating income (loss)	1,509	(846)	(19)	(4,041)
Interest and other income, net	189	143	588	336
Income (loss) before income taxes and equity loss in investee	1,698	(703)	569	(3,705)
Provision for (benefit from) income taxes	61	(318)	81	(852)
Income (loss) before equity loss in investee	1,637	(385)	488	(2,853)
Equity loss in investee	(175)	(210)	(603)	(701)
Net income (loss)	$ 1,462	$ (595)	$ (115)	$ (3,554)
Net income (loss) per common share:
Basic	$ 0.08	$ (0.03)	$ (0.01)	$ (0.20)
Diluted	$ 0.08	$ (0.03)	$ (0.01)	$ (0.20)
Weighted-average common shares:
Basic	18,501	18,012	18,358	17,931
Diluted	19,456	18,012	18,358	17,931

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Comprehensive Income (Loss) (unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Statement Of Income And Comprehensive Income [Abstract]
Net income (loss)	$ 1,462	$ (595)	$ (115)	$ (3,554)
Other comprehensive income (loss):
Foreign currency translation loss	(17)	(23)	(16)	(44)
Net unrealized gain (loss) on marketable securities, net of tax	(7)	48	230	31
Comprehensive income (loss)	$ 1,438	$ (570)	$ 99	$ (3,567)

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Stockholders' Equity (unaudited) - USD ($) $ in Thousands	Total	Stockholders' Equity	Additional Paid-In Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Beginning Balance at Dec. 31, 2017	$ 54,178	$ 2	$ 111,884	$ (44)	$ (57,664)
Beginning Balance, Shares at Dec. 31, 2017		17,847,000
Equity-based compensation	545		545
Exercise of common stock options	2		2
Exercise of common stock options, Shares		5,000
Restricted stock awards, Shares		24,000
Cumulative effect of accounting change	327				327
Cumulative tax effect of accounting change	(74)				(74)
Other comprehensive gain (loss), net	(43)			(43)
Net income (loss)	(1,910)				(1,910)
Ending Balance at Mar. 31, 2018	53,025	$ 2	112,431	(87)	(59,321)
Ending Balance, Shares at Mar. 31, 2018		17,876,000
Beginning Balance at Dec. 31, 2017	54,178	$ 2	111,884	(44)	(57,664)
Beginning Balance, Shares at Dec. 31, 2017		17,847,000
Net income (loss)	(3,554)
Ending Balance at Sep. 30, 2018	52,580	$ 2	113,600	(57)	(60,965)
Ending Balance, Shares at Sep. 30, 2018		18,057,000
Beginning Balance at Mar. 31, 2018	53,025	$ 2	112,431	(87)	(59,321)
Beginning Balance, Shares at Mar. 31, 2018		17,876,000
Equity-based compensation	573		573
Exercise of common stock options	7		7
Exercise of common stock options, Shares		18,000
Restricted stock awards, Shares		69,000
Other comprehensive gain (loss), net	5			5
Net income (loss)	(1,049)				(1,049)
Ending Balance at Jun. 30, 2018	52,561	$ 2	113,011	(82)	(60,370)
Ending Balance, Shares at Jun. 30, 2018		17,963,000
Equity-based compensation	588		588
Exercise of common stock options	1		1
Exercise of common stock options, Shares		6,000
Restricted stock awards, Shares		88,000
Other comprehensive gain (loss), net	25			25
Net income (loss)	(595)				(595)
Ending Balance at Sep. 30, 2018	52,580	$ 2	113,600	(57)	(60,965)
Ending Balance, Shares at Sep. 30, 2018		18,057,000
Beginning Balance at Dec. 31, 2018	$ 51,152	$ 2	114,203	(35)	(63,018)
Beginning Balance, Shares at Dec. 31, 2018	18,172,000	18,172,000
Equity-based compensation	$ 583		583
Exercise of common stock options	4		4
Exercise of common stock options, Shares		9,000
Restricted stock awards, Shares		105,000
Other comprehensive gain (loss), net	130			130
Net income (loss)	(1,908)				(1,908)
Ending Balance at Mar. 31, 2019	49,961	$ 2	114,790	95	(64,926)
Ending Balance, Shares at Mar. 31, 2019		18,286,000
Beginning Balance at Dec. 31, 2018	$ 51,152	$ 2	114,203	(35)	(63,018)
Beginning Balance, Shares at Dec. 31, 2018	18,172,000	18,172,000
Net income (loss)	$ (115)
Ending Balance at Sep. 30, 2019	$ 54,526	$ 2	117,478	179	(63,133)
Ending Balance, Shares at Sep. 30, 2019	18,673,000	18,673,000
Beginning Balance at Mar. 31, 2019	$ 49,961	$ 2	114,790	95	(64,926)
Beginning Balance, Shares at Mar. 31, 2019		18,286,000
Equity-based compensation	737		737
Exercise of common stock options	5		5
Exercise of common stock options, Shares		15,000
Restricted stock awards, Shares		92,000
Other comprehensive gain (loss), net	108			108
Net income (loss)	331				331
Ending Balance at Jun. 30, 2019	51,142	$ 2	115,532	203	(64,595)
Ending Balance, Shares at Jun. 30, 2019		18,393,000
Equity-based compensation	951		951
Exercise of common stock options	16		16
Exercise of common stock options, Shares		43,000
Restricted stock awards, Shares		133,000
Issuance of common stock	979		979
Issuance of common stock, Shares		104,000
Other comprehensive gain (loss), net	(24)			(24)
Net income (loss)	1,462				1,462
Ending Balance at Sep. 30, 2019	$ 54,526	$ 2	$ 117,478	$ 179	$ (63,133)
Ending Balance, Shares at Sep. 30, 2019	18,673,000	18,673,000

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Stockholders' Equity (Parenthetical) (unaudited)	Sep. 30, 2019$ / shares
Weighted-Average | Common Stock
Selling price per share	$ 9.37

Condensed Consolidated Statem_5

Condensed Consolidated Statements of Cash Flows (unaudited) - USD ($)	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Cash flow from operating activities:
Net loss	$ (115,000)	$ (3,554,000)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Equity-based compensation	2,271,000	1,706,000
Depreciation	1,549,000	1,625,000
Noncash lease expense	306,000
Loss on disposal of fixed asset	11,000	88,000
Amortization of premium of marketable securities	52,000	239,000
Provision for bad debt	37,000	230,000
Deferred taxes	(21,000)	(887,000)
Equity loss in investee	603,000	701,000
Other	41,000	18,000
Changes in operating assets and liabilities:
Accounts receivable	588,000	(1,993,000)
Other current and long-term assets	450,000	215,000
Accounts payable	(91,000)	(175,000)
Accrued liabilities	202,000	334,000
Income tax payable	60,000
Operating lease liabilities	(310,000)
Net cash provided by (used in) operations	5,633,000	(1,453,000)
Cash flow from investing activities:
Purchases of fixed assets	(721,000)	(2,199,000)
Purchase of marketable securities	(11,846,000)	(13,165,000)
Maturities of marketable securities	19,600,000	19,360,000
Purchase of equipment contributed to Equity Method Investee		(510,000)
Net cash provided by investing activities	7,033,000	3,486,000
Cash flow from financing activities:
Proceeds from public offerings of common stock, net of issuance costs	1,110,000
Proceeds from exercise of stock options	26,000	10,000
Net cash provided by financing activities	1,136,000	10,000
Effect of exchange rate changes on cash and cash equivalents	(16,000)	(44,000)
Net increase in cash	13,786,000	1,999,000
Cash balance at beginning of period	6,736,000	6,490,000
Cash balance at end of period	20,522,000	8,489,000
Supplemental disclosures of cash flow information:
Income taxes paid	20,000	1,000
Supplemental disclosures of non-cash investing and financing activities:
Purchases of fixed assets in accounts payable	880,000	$ 73,000
Operating lease right-of-use assets obtained in exchange for lease liabilities	110,000
Public offerings costs included in accounts payable	$ 131,000

Overview and Basis of Presentat

Overview and Basis of Presentation	9 Months Ended
	Sep. 30, 2019
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Overview and Basis of Presentation	Note 1. Overview and Basis of Presentation The accompanying condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”). These financial statements include the assets, liabilities, revenues and expenses of all wholly-owned subsidiaries and entities in which the Company has a controlling financial interest or is deemed to be the primary beneficiary. In determining whether the Company is the primary beneficiary of an entity, the Company applies a qualitative approach that determines whether it has both (1) the power to direct the economically significant activities of the entity and (2) the obligation to absorb losses of, or the right to receive benefits from, the entity that could potentially be significant to that entity. The Company uses the equity method to account for its investments in entities that it does not control, but in which it has the ability to exercise significant influence over operating and financial policies. All significant intercompany accounts and transactions are eliminated from the accompanying condensed consolidated financial statements. Nature of the Business Fulgent Genetics, Inc., together with its subsidiaries (collectively referred to as the “Company,” unless otherwise noted or the context otherwise requires), is a growing technology company offering comprehensive genetic testing and providing physicians with clinically actionable diagnostic information they can use to improve the quality of patient care. The Company has developed a proprietary technology platform that allows it to offer a broad and flexible test menu and continually expand and improve its proprietary genetic reference library, while maintaining accessible pricing, high accuracy and competitive turnaround times. Combining next generation sequencing, or NGS, with its technology platform, the Company performs full-gene sequencing with deletion/duplication analysis in single-gene tests; pre-established, multi-gene, disease-specific panels; and customized panels that can be tailored to meet specific customer needs. The Company believes its test menu offers more genes for testing than its competitors in today’s market, which enables it to provide expansive options for test customization and clinically actionable results. A cornerstone of the Company’s business is its ability to provide expansive options and flexibility for all clients’ unique genetic testing needs. Unaudited Interim Financial Information The accompanying unaudited interim condensed consolidated financial statements have been prepared on the same basis as the Company’s financial statements and, in the opinion of management, all adjustments, which normal recurring , necessary for a fair of the financial position and results of results for periods are not necessarily indicative of the results be expected for The accompanying condensed consolidated balance sheet as of December 31, 2018 has been derived from the Company’s audited consolidated financial statements at that date but does not include all of the disclosures required by U.S. GAAP. with the Company’s audited consolidated financial statements included in the 2018 Annual Report, including the notes thereto.

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2019
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Note 2. Summary of Significant Accounting Policies See the summary Company’s significant accounting policies set forth in the notes to its consolidated included in the 2018 Annual Report. Use of Estimates The preparation of condensed consolidated financial statements in conformity with U.S. GAAP requires management to make certain estimates, judgments and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements, as well as the reported amounts of revenue and expenses during the reporting periods. These estimates, judgments and assumptions are based on historical data and experience available at the date of the accompanying condensed consolidated financial statements, as well as various other factors management believes to be reasonable under the circumstances. Actual results could differ from these estimates. On an on-going basis, management evaluates its estimates, primarily those related to: (i) revenue recognition criteria, (ii) accounts receivable and allowances for doubtful accounts, (iii) the useful lives of fixed assets, (iv) estimates of tax liabilities and (v) equity method investments. Foreign Currency Translation and Foreign Currency Transactions The Company translates the assets and liabilities of its non-U.S. dollar functional currency subsidiaries into U.S. dollars using exchange rates in effect at the end of each period. Expenses for these subsidiaries are translated using rates that approximate those in effect during the period. Gains and losses from these translations are recognized in foreign currency translation included in other comprehensive income (loss) in the accompanying condensed consolidated statements of stockholders’ equity. Gains and losses from these translations were not significant in the three and nine months ended September 30, 2019 and 2018. The Company and its subsidiaries that use the U.S. dollar as their functional currency remeasure monetary assets and liabilities at exchange rates in effect at the end of each period, and inventories, property and nonmonetary assets and liabilities at historical rates. Losses from these remeasurements were not significant Leases The Company determines if an arrangement is a lease at inception. Operating leases are included as operating lease right-of-use (“ROU”) assets, operating lease liabilities, short-term, and operating lease liabilities, long-term, on the Company’s condensed consolidated balance sheets. ROU lease assets represent the Company’s right to use an underlying asset for the lease term and lease liabilities represent the Company’s obligation to make lease payments arising from the lease. Operating ROU lease assets and liabilities are recognized at the commencement date based on the present value of lease payments over the lease term, including options to extend the lease when it is reasonably certain that the Company will exercise that option. The Company uses its incremental borrowing rate based on the information available at the commencement date in determining the present value of lease payments since its leases do not provide an implicit rate. The ROU lease asset includes any base rent payments made and excludes lease incentives and variable operating expenses. Lease expense for lease payments is recognized on a straight-line basis over the lease term. Concentration of Customers In certain periods, a small number of customers has accounted for a significant portion of the Company’s revenue. In the three and nine months ended September 30, 2019 , after aggregating customers that are under common control or are affiliates, one customer contributed 40% and 33%, respectively, of the Company’s revenue. three and nine months ended September 30, 2018 aggregating customers that are under common control or are affiliates, one customer contributed 13% of the Company’s revenue. Revenue from Contracts with Customers Disaggregation of Revenue The Company classifies its customers into three payor types, Clinical Institutional, Patients who pay directly or Clinical Insurance, as the Company believes this best depicts how the nature, amount, timing, and uncertainty of its revenue and cash flows are affected by economic factors. The following table summarizes revenue from contracts with customers by payor type for the three and nine months of 2019 and 2018 Three months ended September 30, Nine months ended September 30, 2019 2018 2019 2018 (in thousands) Genetic Testing Services by payor Institutional $ 10,031 $ 5,334 $ 23,310 $ 14,594 Patient 128 148 373 407 Insurance 188 143 458 677 Total Revenue $ 10,347 $ 5,625 $ 24,141 $ 15,678 Contract Balances Receivables from contracts with customers - As of September 30, 2019 and December 31, 2018, receivables from contracts with customers were approximately $5.3 million and $5.9 million, respectively, and are included within Trade accounts receivable on the Condensed Consolidated Balance Sheets. Contracts assets and liabilities - As of September 30, 2019 and December 31, 2018, contract assets from contracts with customers were $150,000, associated with contract execution and included in other current assets in the accompanying Condensed Consolidated Balance Sheets. Contract liabilities are recorded when the Company receives payment prior to completing its obligation to transfer goods or services to a customer. The Company had $369,000 and $166,000 of contract liability, which is part of Accrued liabilities in the accompanying Condensed Consolidated Balance Sheets, as of September 30, 2019 and December 31, 2018, respectively. Revenues of $48,000 and $26,000 for the three months and $37,000 and $16,000 for the nine months were recognized for the periods ended September 30, 2019 and 2018, respectively, related to contract liabilities at the beginning of the respective periods. Transaction Price Allocated to Future Performance Obligations The Company does not have material future obligations associated with genetic testing services that extend beyond one year. Recent Accounting Pronouncements Adopted ASU No. 2016-02 In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842), which supersedes ASC 840, Leases See Note 9, Leases, for further information. ASU No. 2017-08 In March 2017, the FASB issued ASU No. 2017-08, Receivables–Nonrefundable Fees and Other Costs (Subtopic 310-20) ASU No. 2018-02 In February 2018, the FASB issued ASU 2018-02 Income Statement - Reporting Comprehensive Income (ASC 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income (AOCI), Recent Accounting Pronouncements The Company evaluates all Accounting Standards Updates (ASUs) issued by the Financial Accounting Standards Board (FASB) for consideration of their applicability. ASUs not included in the Company’s disclosures were assessed and determined to be either not applicable or are not expected to have a material impact on its Condensed Consolidated Financial Statements. ASU No. 2016-13 In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments-Credit Losses: Measurement of Credit Losses on Financial Instruments ASU 2019-05, Financial Instruments - Credit Losses (Topic 326): Targeted Transition Relief ASU No. 2018-15 In August 2018, the FASB issued ASU No. 2018-15, Intangibles-Goodwill and Other-Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract

Marketable Securities

Marketable Securities	9 Months Ended
	Sep. 30, 2019
Investments Debt And Equity Securities [Abstract]
Marketable Securities	Note 3. Marketable Securities The Company’s marketable securities consisted of the following: September 30, 2019 Amortized Cost Basis Unrealized Gains Unrealized Losses Aggregate Fair Value (in thousands) Marketable securities: Short-term Money market accounts $ 11,628 — — $ 11,628 Corporate debt securities 11,569 28 (1 ) 11,596 Less: Cash equivalents (11,628 ) — — (11,628 ) Total short-term marketable securities 11,569 28 (1 ) 11,596 Corporate debt securities 11,354 133 — 11,487 Total long-term marketable securities 11,354 133 — 11,487 Total marketable securities $ 22,923 $ 161 $ (1 ) $ 23,083 December 31, 2018 Amortized Cost Basis Unrealized Gains Unrealized Losses Aggregate Fair Value (in thousands) Marketable securities: Short-term Money market accounts $ 2,692 $ — $ — $ 2,692 United States Treasury 990 — — 990 U.S. government agency securities 790 — — 790 Corporate debt securities 22,613 1 (96 ) 22,518 Less: Cash equivalents (2,692 ) — — (2,692 ) Total short-term marketable securities 24,393 1 (96 ) 24,298 Corporate debt securities 6,383 11 (8 ) 6,386 Total long-term marketable securities 6,383 11 (8 ) 6,386 Total marketable securities $ 30,776 $ 12 $ (104 ) $ 30,684 Management determined that the gross unrealized losses of $1,000 on the Company’s marketable securities as of September 30, 2019 were temporary in nature. Gross unrealized losses on the Company’s marketable securities were $104,000 as of December 31, 2018. The Company currently does not intend to sell these securities prior to maturity and does not consider these investments to be other-than-temporarily impaired as of September 30, 2019.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2019
Fair Value Disclosures [Abstract]
Fair Value Measurements	Note 4. Fair Value Measurements The authoritative guidance on fair value measurements establishes a framework with respect to measuring assets and liabilities at fair value on a recurring basis and non-recurring basis. Under the framework, fair value is defined as the exit price, or the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants, as of the measurement date. The framework also establishes a three-tier hierarchy for inputs used in measuring fair value that maximizes the use of observable inputs and minimizes the use of unobservable inputs by requiring that the most observable inputs be used when available. Observable inputs are inputs market participants would use in valuing the asset or liability and are developed based on market data obtained from sources independent of the Company. Unobservable inputs are inputs that reflect the Company’s assumptions about the factors market participants would use in valuing the asset or liability and are developed based on the best information available in the circumstances. The hierarchy consists of the following three levels: Level 1: Inputs are quoted prices (unadjusted) in active markets for identical assets or liabilities that the reporting entity can access at the measurement date. Level 2: Inputs are inputs other than quoted prices included within Level 1 that are observable for the asset or liability, either directly or indirectly. Level 3: Inputs are unobservable inputs for the asset or liability. The following tables present information about the Company’s financial assets measured at fair value on a recurring basis, based on the three-tier fair value hierarchy: September 30, 2019 Total Level 1 Level 2 Level 3 (in thousands) Marketable securities and cash equivalents: Corporate debt securities $ 23,083 $ — $ 23,083 $ — Money market accounts 11,628 11,628 — — Total marketable securities and cash equivalents $ 34,711 $ 11,628 $ 23,083 $ — December 31, 2018 Total Level 1 Level 2 Level 3 (in thousands) Marketable securities and cash equivalents: Corporate debt securities $ 28,904 $ — $ 28,904 $ — United States Treasury 990 — 990 — U.S. government agency securities 790 — 790 — Money market accounts 2,692 2,692 — — Total marketable securities and cash equivalents $ 33,376 $ 2,692 $ 30,684 $ — The Company’s Level 1 assets include money market instruments and are valued based upon observable market prices. Level 2 assets consist of United States Treasury, U.S. government agency securities, and corporate debt securities. Level 2 securities are valued based upon observable inputs that include reported trades, broker/dealer quotes, bids and offers. As of September 30, 2019, the Company had no investments that were measured using unobservable (Level 3) inputs. There were no transfers between fair value measurement levels during the nine months ended September 30, 2019. Gross unrealized gains or losses for cash equivalents and marketable securities as of September 30, 2019 September 30, 2019 September 30

Fixed Assets

Fixed Assets	9 Months Ended
	Sep. 30, 2019
Property Plant And Equipment [Abstract]
Fixed Assets	Note 5. Fixed Assets Major classes of fixed assets consisted of the following: September 30, December 31, Useful Lives 2019 2018 (in thousands) Computer hardware 3 Years $ 1,702 $ 1,579 Computer software 3 Years 541 495 Medical lab equipment 5 Years 8,144 8,136 Furniture and fixtures 5 Years 234 233 Leasehold improvements Shorter of lease term or estimated useful life 815 802 Assets not yet placed in service 2,402 1,087 Total 13,838 12,332 Less: Accumulated depreciation (7,442 ) (5,886 ) Property and equipment, net $ 6,396 $ 6,446 Depreciation expense on fixed assets totaled $503,000 and $547,000 for the three months and $1.5 million and $1.6 million for the nine months ended September 30, 2019 and 2018, respectively.

Significant Balance Sheet Accou

Significant Balance Sheet Accounts	9 Months Ended
	Sep. 30, 2019
Balance Sheet Related Disclosures [Abstract]
Significant Balance Sheet Accounts	Note 6. Significant Balance Sheet Accounts Other current assets consisted of the following: September 30, 2019 December 31, 2018 (in thousands) Reagents $ 244 $ 314 Contract assets 150 150 Prepaid expenses 1,160 556 Prepaid income taxes 41 1,251 Marketable securities interest receivable 173 220 Other receivable 27 70 Total $ 1,795 $ 2,561 Reagents are used for DNA sequencing applications in the Company’s DNA sequencing equipment.

Reporting Segment and Geographi

Reporting Segment and Geographic Information	9 Months Ended
	Sep. 30, 2019
Segment Reporting [Abstract]
Reporting Segment and Geographic Information	Note 7. Reporting Segment and Geographic Information The Company views its operations and manages its business in one reporting segment. Long-lived assets were primarily located in the United States as of September 30, 2019 with an insignificant amount located in Canada. All long-lived assets were located in the United States as of December 31, 2018. Revenue by region during the three and nine months ended September 30, 2019 and 2018 were as follows: Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 (in thousands) Revenue: United States $ 8,479 $ 3,273 $ 18,779 $ 9,099 Foreign: Canada 548 1,120 1,602 3,160 Other Countries 1,320 1,232 3,760 3,419 Total $ 10,347 $ 5,625 $ 24,141 $ 15,678

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2019
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	Note 8. Commitments and Contingencies Operating Leases See Note 9, Leases, for further information. FF Gene Biotech See Note 14 for a description of the Company’s commitments related to its joint venture, FF Gene Biotech (as defined in Note 14). Purchase Obligations As of September 30, 2019, the Company had non-cancelable purchase obligations of $3.7 million for reagents and other supplies, of which, $3.1 million is payable within twelve months, and $542,000 is payable within the next twenty-four months. Contingencies From time to time, the Company may be subject to legal proceedings and claims arising in the ordinary course of business. Management does not believe that the outcome of any of these matters will have a material effect on the Company’s consolidated financial position, results of operations or cash flows.

Leases

Leases	9 Months Ended
	Sep. 30, 2019
Leases [Abstract]
Leases	Note 9. Leases The Company has various non-cancelable operating leases with varying terms through August 2023 primarily for office space. The Company has options to renew some of these leases for three years after their expiration. The determination of whether an arrangement contains a lease is made at inception by evaluating whether the arrangement conveys the right to use an identified asset and whether the Company obtains substantially all of the economic benefits from and has the ability to direct the use of the asset. The Company’s headquarters is located in Temple City, California, which is comprised of various corporate offices and a laboratory certified under the Clinical Laboratory Improvement Amendments of 1988 (“CLIA”), accredited by the College of American Pathologists (“CAP”) and licensed by the State of California Department of Public Health. Additional offices are located in El Monte, California and Atlanta, Georgia and are used for certain research and development, customer service, report generation and other administrative functions. Rent expense, including sublease consideration, was approximately $140,000 and $70,000 for the three months ended and $405,000 and $298,000 for the nine months ended September 30, 2019 and 2018, respectively. The Company adopted new accounting standard ASC 842, Leases As the Company’s leases do not provide an implicit rate, the Company uses its incremental borrowing rate based on information available at the commencement date in determining the discount rate used to calculate present value lease payment. The Company determined its incremental borrowing rate based on inquiries with its bank. The Company’s lease agreements do not contain any residual value guarantees, material restrictive covenants, bargain purchase options or asset retirement obligations. Lease expense for the Company’s operating leases is recognized on a straight-line basis over the lease term. The Company’s leases do not contain variable lease payments. The Company does not have any short-term leases and thus has excluded short-term costs from the table below. Other than the new lease in Georgia, the Company did not enter into any new leases during the nine months ended September 30 The following was operating lease expense: Three months ended September 30, 2019 Nine months ended September 30, 2019 Operating lease cost $ 146 $ 438 Supplemental cash flow information related to leases was the following: Three months ended September 30, 2019 Nine months ended September 30, 2019 Cash paid for amounts included in the measurement of lease liabilities $ 140 $ 391 Noncash lease expense $ 105 $ 306 Right-of-use assets obtained in exchange for new operating lease liabilities $ 110 $ 110 Supplemental balance sheet information related to leases was the following: September 30, 2019 Weighted average remaining lease term - operating leases 5.8 years Weighted average discount rate - operating leases 6.25 % The following is a maturity analysis of operating lease liabilities using undiscounted cash flows on an annual basis with renewal periods included: Operating Leases (in thousands) Year Ending December 31, 2019 (remaining 3 months) $ 142 2020 575 2021 591 2022 597 2023 567 2024 330 Thereafter 532 Total lease payments 3,334 Less imputed interest (559 ) Total $ 2,775 Future minimum payments under non-cancelable operating leases as of December 31, 2018 are as follows: Amounts (in thousands) Year ending December 31, 2019 $ 560 2020 559 2021 550 2022 558 2023 567 Thereafter 862 Total minimum lease payments $ 3,656

Equity-Based Compensation

Equity-Based Compensation	9 Months Ended
	Sep. 30, 2019
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Equity-Based Compensation	Note 10. Equity-Based Compensation The Company has included equity-based compensation expense as part of cost of revenue and operating expenses in the accompanying condensed consolidated statements of operations as follows: Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 (in thousands) Cost of revenue $ 174 $ 121 $ 483 $ 396 Research and development 279 214 690 517 Selling and marketing 332 115 643 336 General and administrative 166 138 455 457 Total $ 951 $ 588 $ 2,271 $ 1,706

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2019
Income Tax Disclosure [Abstract]
Income Taxes	Note 11. Income Taxes Provision for income taxes consists of U.S. federal and state income taxes. A deferred tax liability is recognized for all taxable temporary differences, and a deferred tax asset is recognized for all deductible temporary differences, operating losses and tax credit carryforwards. A valuation allowance is provided when it is more likely than not that some portion or all of a deferred tax asset will not be realized. In order to determine the Company’s quarterly provision for income taxes, the Company used an estimated annual effective tax rate for the full fiscal year ending December 31, 2019, which is based on expected annual income and statutory tax rates in the various jurisdictions in which the Company operates, adjusted for discrete items recognized during the period. Certain significant or unusual items are separately recognized in the quarter during which they occur and can cause the effective tax rate to vary from quarter to quarter. The Company’s effective tax rate was 4% and 14% for the three and nine months ended September 30, 2019, respectively, compared with 45% and 23% for the three and nine months ended September 30, 2018, respectively. The change in effective tax rate for the three months and nine months ended September 30, 2019, was primarily attributable to the full valuation allowance.

Loss Per Share

Loss Per Share	9 Months Ended
	Sep. 30, 2019
Earnings Per Share [Abstract]
Loss per Share	Note 12. Loss per Share The following table presents the calculation of basic and diluted loss per share Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 (in thousands, except per share data) Net income (loss) $ 1,462 $ (595 ) $ (115 ) $ (3,554 ) Weighted-average common shares—outstanding, basic 18,501 18,012 18,358 17,931 Weighted-average common shares—outstanding, diluted 19,456 18,012 18,358 17,931 Net income (loss) per common share, basic $ 0.08 $ (0.03 ) $ (0.01 ) $ (0.20 ) Net income (loss) per common share, diluted $ 0.08 $ (0.03 ) $ (0.01 ) $ (0.20 ) The following securities have been excluded from the calculation of diluted loss per share because their effect would have been anti-dilutive: Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 (in thousands) Options 19 429 351 424 RSUs 20 1,045 1,056 914 The anti-dilutive shares described above were calculated using the treasury stock method. During the three months ended September 30, 2018 and nine months ended September 30, 2019 and 2018, the Company had outstanding stock options and RSUs that were excluded from the weighted-average share calculation due to the Company’s net loss position.

Related Party

Related Party	9 Months Ended
	Sep. 30, 2019
Related Party Transactions [Abstract]
Related Party	Note 13. Related Party Dr. Yun Yen, who is a member of the Company’s Board of Directors and a stockholder, serves as the President and Chairman of the Board for the Sino-American Cancer Foundation (the “Foundation”) and served as the President for the Taipei Medical University (the “University”), from August 1, 2011 through July 31, 2016. From time to time, the Company performs research testing services, on an arms-length basis, for the Foundation. The Company recognized zero in revenue during the three months ended and $2,500 and zero for the nine months ended September 30, 2019 and 2018, respectively, as consideration for such services. Additionally, the Company subleased certain of its headquarters facilities to the Foundation. The Company recognized zero and $16,000 for the three months and $16,000 and $24,000 for the nine months ended September 30, 2019 and 2018, respectively, as consideration for such sublease. As of September 30, 2019, and December 31, 2018, $2,500 and zero, respectively, was owed to the Company by the Foundation in connection with these relationships. From time to time, the Company performs genetic sequencing services, on an arms-length basis, for the University. The Company recognized $29,000 and $37,000 for the three months ended and $51,000 and $53,000 for the nine months ended September 30, 2019 and 2018, respectively, as consideration for such services. As of September 30, 2019, and December 31, 2018, $37,000 and $51,000, respectively, was owed to the Company by the University in connection with this relationship. As more fully described in Note 14, in April 2017, the Company, through an affiliated company formed for the purpose of the relationship, entered into a cooperation agreement (the “JV Agreement”) with Xilong Scientific Co., Ltd. (“Xilong Scientific”) and Fuzhou Jinqiang Investment Partnership (LP) (“FJIP”) to form a joint venture under the laws of the People’s Republic of China (“PRC”) called Fujian Fujun Gene Biotech Co., Ltd. (“FF Gene Biotech”). Xilong Scientific is an affiliate of Xi Long USA, Inc., a large stockholder of the Company that, as of , 2019, owned 11% of the outstanding shares of the Company’s common stock, and FJIP is owned by key management of FF Gene Biotech, including Dr. Han Lin Gao, the Chief Scientific Officer and a large stockholder of the Company and the owner of approximately 25% of FJIP. Fulgent Pharma utilizes space in the facility at which the Company’s laboratory and corporate headquarters are located. Since the completion of the Pharma Split-Off, Fulgent Pharma reimburses us for the portion of the rent we pay that is attributable to the space it uses, which amounts are not significant. As of September 30, 2019, and December 31, 2018, $29,000 and $22,000, respectively, was due from Fulgent Pharma as a result of this arrangement, which is recorded in Other receivable in Other current assets in the accompanying condensed consolidated balance sheets.

Equity Method Investments

Equity Method Investments	9 Months Ended
	Sep. 30, 2019
Equity Method Investments And Joint Ventures [Abstract]
Equity Method Investments	Note 14. Equity Method Investments In April 2017, the Company, through an affiliated company formed for the purpose of the relationship, entered into the JV Agreement with Xilong Scientific and FJIP to form FF Gene Biotech, a joint venture formed under the laws of the PRC to offer genetic testing services to customers in the PRC. Pursuant to the terms of the JV Agreement, the Company has agreed to contribute to FF Gene Biotech genetic sequencing and other equipment with a total cost of 60,000,000 renminbi (“ RMB”) over a five-year period for a 30% ownership interest in FF Gene Biotech, previously three-year per original agreement and amended in April 2019. Xilong Scientific has agreed to contribute to FF Gene Biotech 102,000,000 RMB over a five-year period for a 51% ownership interest in the FF Gene Biotech, previously three-year per original agreement and amended in April 2019. FJIP has agreed to contribute to FF Gene Biotech 19,000,000 RMB over a ten-year period for a 19% ownership interest in FF Gene Biotech, previously five-year per original agreement and amended in April 2019. The Company’s maximum exposure to fund losses of FF Gene Biotech as a result of its minority ownership of this entity is equal to its contribution obligation under the JV Agreement as described above. As of , 2019, 40,300,000 RMB (or approximately $5.7 million U.S. dollars) remains to be contributed to the investee under the terms of the JV agreement. To date, the Company has purchased and contributed equipment with an aggregate fair value of $3.0 million pursuant to its contribution commitment under the JV Agreement. The Company accounted for this contribution in accordance with ASC 845, Nonmonetary Transactions , and recorded an investment based on the fair value of the contributed equipment, which is the same as carryover basis. The Company concluded FF Gene Biotech is a variable interest entity not have significant and Judgment regarding the level of influence over FF Gene Biotech includes consideration of key factors such as the Company's ownership interest, representation on the board of directors or other management body and participation in policy-making decisions. The Company accounts for its 30% interest in FF Gene Biotech using the equity method of accounting. The Company recorded its proportionate share of the losses of FF Gene Biotech in the three and nine months ended , 2019 in the accompanying condensed consolidated statements of operations, and recorded its contribution to date, net of its proportionate share in the accumulated losses of FF Gene Biotech, in the accompanying condensed consolidated balance sheet as of , 2019. The Company entered into a license agreement with FF Gene Biotech, pursuant to which it granted FF Gene Biotech a license to use certain of the Company’s clinical molecular diagnostic gene detection technology and related software and proprietary reference library of genetic information, along with any improvements on this technology that they may develop during the term of the license agreement. Under the license agreement, FF Gene Biotech will pay to the Company, on a quarterly basis, certain royalties based on the revenues of FF Gene Biotech. The license agreement expired on December 31, 2018. The Company earned $12,000 and $47,000 for royalties under the license agreement for the three and ended September 30, 2018, respectively. Equity method investments as of September 30 September 30, 2019 December 31, 2018 Carrying Value Ownership Percentage Carrying Value Ownership Percentage (in thousands) FF Gene Biotech $ 909 30 % $ 1,512 30 % Total equity method investments $ 909 30 % $ 1,512 30 % Summary Financial Information Summary financial information for FF Gene Biotech is as follows: Nine Months Ended September 30 2019 2018 Consolidated Statements of Operations Data: (in thousands) Net Sales $ 2,126 $ 577 Gross Profit 1,123 30 Net Loss (2,322 ) (2,327 ) Share of loss from investments accounted for using the equity method (603 ) (701 )

Equity Distribution Agreement

Equity Distribution Agreement	9 Months Ended
	Sep. 30, 2019
Equity [Abstract]
Equity Distribution Agreement	Note 15. Equity Distribution Agreement In August 2019, the Company entered into an Equity Distribution Agreement with Piper Jaffray & Co., as sales agent (“Piper”), pursuant to which the Company may offer and sell, from time to time through Piper, shares of its common stock having an aggregate offering price of up to $30.0 million. Piper is eligible to receive a commission of up to 3% of gross proceeds received by the Company for sales pursuant to the Equity Distribution Agreement. During the quarter ended September 30, 2019, the Company sold an aggregate of 104,390 shares of its common stock pursuant to the Equity Distribution Agreement at a weighted-average selling price of $12.14 per share, which resulted in $979,000 of net proceeds to the Company. Shares sold under the Equity Distribution Agreement are offered and sold pursuant to the Company’s Form S-3 Registration Statement filed with the SEC on August 12, 2019 and declared effective on August 23, 2019, and a prospectus supplement and accompanying base prospectus filed with the Securities and Exchange Commission on August 30, 2019.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2019
Accounting Policies [Abstract]
Use of Estimates	Use of Estimates The preparation of condensed consolidated financial statements in conformity with U.S. GAAP requires management to make certain estimates, judgments and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements, as well as the reported amounts of revenue and expenses during the reporting periods. These estimates, judgments and assumptions are based on historical data and experience available at the date of the accompanying condensed consolidated financial statements, as well as various other factors management believes to be reasonable under the circumstances. Actual results could differ from these estimates. On an on-going basis, management evaluates its estimates, primarily those related to: (i) revenue recognition criteria, (ii) accounts receivable and allowances for doubtful accounts, (iii) the useful lives of fixed assets, (iv) estimates of tax liabilities and (v) equity method investments.
Foreign Currency Translation and Foreign Currency Transactions	Foreign Currency Translation and Foreign Currency Transactions The Company translates the assets and liabilities of its non-U.S. dollar functional currency subsidiaries into U.S. dollars using exchange rates in effect at the end of each period. Expenses for these subsidiaries are translated using rates that approximate those in effect during the period. Gains and losses from these translations are recognized in foreign currency translation included in other comprehensive income (loss) in the accompanying condensed consolidated statements of stockholders’ equity. Gains and losses from these translations were not significant in the three and nine months ended September 30, 2019 and 2018. The Company and its subsidiaries that use the U.S. dollar as their functional currency remeasure monetary assets and liabilities at exchange rates in effect at the end of each period, and inventories, property and nonmonetary assets and liabilities at historical rates. Losses from these remeasurements were not significant
Leases	Leases The Company determines if an arrangement is a lease at inception. Operating leases are included as operating lease right-of-use (“ROU”) assets, operating lease liabilities, short-term, and operating lease liabilities, long-term, on the Company’s condensed consolidated balance sheets. ROU lease assets represent the Company’s right to use an underlying asset for the lease term and lease liabilities represent the Company’s obligation to make lease payments arising from the lease. Operating ROU lease assets and liabilities are recognized at the commencement date based on the present value of lease payments over the lease term, including options to extend the lease when it is reasonably certain that the Company will exercise that option. The Company uses its incremental borrowing rate based on the information available at the commencement date in determining the present value of lease payments since its leases do not provide an implicit rate. The ROU lease asset includes any base rent payments made and excludes lease incentives and variable operating expenses. Lease expense for lease payments is recognized on a straight-line basis over the lease term.
Concentration of Customers	Concentration of Customers In certain periods, a small number of customers has accounted for a significant portion of the Company’s revenue. In the three and nine months ended September 30, 2019 , after aggregating customers that are under common control or are affiliates, one customer contributed 40% and 33%, respectively, of the Company’s revenue. three and nine months ended September 30, 2018 aggregating customers that are under common control or are affiliates, one customer contributed 13% of the Company’s revenue.
Revenue from Contracts with Customers	Revenue from Contracts with Customers Disaggregation of Revenue The Company classifies its customers into three payor types, Clinical Institutional, Patients who pay directly or Clinical Insurance, as the Company believes this best depicts how the nature, amount, timing, and uncertainty of its revenue and cash flows are affected by economic factors. The following table summarizes revenue from contracts with customers by payor type for the three and nine months of 2019 and 2018 Three months ended September 30, Nine months ended September 30, 2019 2018 2019 2018 (in thousands) Genetic Testing Services by payor Institutional $ 10,031 $ 5,334 $ 23,310 $ 14,594 Patient 128 148 373 407 Insurance 188 143 458 677 Total Revenue $ 10,347 $ 5,625 $ 24,141 $ 15,678 Contract Balances Receivables from contracts with customers - As of September 30, 2019 and December 31, 2018, receivables from contracts with customers were approximately $5.3 million and $5.9 million, respectively, and are included within Trade accounts receivable on the Condensed Consolidated Balance Sheets. Contracts assets and liabilities - As of September 30, 2019 and December 31, 2018, contract assets from contracts with customers were $150,000, associated with contract execution and included in other current assets in the accompanying Condensed Consolidated Balance Sheets. Contract liabilities are recorded when the Company receives payment prior to completing its obligation to transfer goods or services to a customer. The Company had $369,000 and $166,000 of contract liability, which is part of Accrued liabilities in the accompanying Condensed Consolidated Balance Sheets, as of September 30, 2019 and December 31, 2018, respectively. Revenues of $48,000 and $26,000 for the three months and $37,000 and $16,000 for the nine months were recognized for the periods ended September 30, 2019 and 2018, respectively, related to contract liabilities at the beginning of the respective periods. Transaction Price Allocated to Future Performance Obligations The Company does not have material future obligations associated with genetic testing services that extend beyond one year.
Recent Accounting Pronouncements Adopted and Recent Accounting Pronouncements	Recent Accounting Pronouncements Adopted ASU No. 2016-02 In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842), which supersedes ASC 840, Leases See Note 9, Leases, for further information. ASU No. 2017-08 In March 2017, the FASB issued ASU No. 2017-08, Receivables–Nonrefundable Fees and Other Costs (Subtopic 310-20) ASU No. 2018-02 In February 2018, the FASB issued ASU 2018-02 Income Statement - Reporting Comprehensive Income (ASC 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income (AOCI), Recent Accounting Pronouncements The Company evaluates all Accounting Standards Updates (ASUs) issued by the Financial Accounting Standards Board (FASB) for consideration of their applicability. ASUs not included in the Company’s disclosures were assessed and determined to be either not applicable or are not expected to have a material impact on its Condensed Consolidated Financial Statements. ASU No. 2016-13 In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments-Credit Losses: Measurement of Credit Losses on Financial Instruments ASU 2019-05, Financial Instruments - Credit Losses (Topic 326): Targeted Transition Relief ASU No. 2018-15 In August 2018, the FASB issued ASU No. 2018-15, Intangibles-Goodwill and Other-Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	9 Months Ended
	Sep. 30, 2019
Accounting Standards Update 2014-09
Summary of Revenue from Contracts with Customers by Payor Type	The following table summarizes revenue from contracts with customers by payor type for the three and nine months of 2019 and 2018 Three months ended September 30, Nine months ended September 30, 2019 2018 2019 2018 (in thousands) Genetic Testing Services by payor Institutional $ 10,031 $ 5,334 $ 23,310 $ 14,594 Patient 128 148 373 407 Insurance 188 143 458 677 Total Revenue $ 10,347 $ 5,625 $ 24,141 $ 15,678

Marketable Securities (Tables)

Marketable Securities (Tables)	9 Months Ended
	Sep. 30, 2019
Investments Debt And Equity Securities [Abstract]
Summary of Marketable Securities	The Company’s marketable securities consisted of the following: September 30, 2019 Amortized Cost Basis Unrealized Gains Unrealized Losses Aggregate Fair Value (in thousands) Marketable securities: Short-term Money market accounts $ 11,628 — — $ 11,628 Corporate debt securities 11,569 28 (1 ) 11,596 Less: Cash equivalents (11,628 ) — — (11,628 ) Total short-term marketable securities 11,569 28 (1 ) 11,596 Corporate debt securities 11,354 133 — 11,487 Total long-term marketable securities 11,354 133 — 11,487 Total marketable securities $ 22,923 $ 161 $ (1 ) $ 23,083 December 31, 2018 Amortized Cost Basis Unrealized Gains Unrealized Losses Aggregate Fair Value (in thousands) Marketable securities: Short-term Money market accounts $ 2,692 $ — $ — $ 2,692 United States Treasury 990 — — 990 U.S. government agency securities 790 — — 790 Corporate debt securities 22,613 1 (96 ) 22,518 Less: Cash equivalents (2,692 ) — — (2,692 ) Total short-term marketable securities 24,393 1 (96 ) 24,298 Corporate debt securities 6,383 11 (8 ) 6,386 Total long-term marketable securities 6,383 11 (8 ) 6,386 Total marketable securities $ 30,776 $ 12 $ (104 ) $ 30,684

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2019
Fair Value Disclosures [Abstract]
Information about Financial Assets Measured at Fair Value on Recurring Basis Based on Three-Tier Fair Value Hierarchy	The following tables present information about the Company’s financial assets measured at fair value on a recurring basis, based on the three-tier fair value hierarchy: September 30, 2019 Total Level 1 Level 2 Level 3 (in thousands) Marketable securities and cash equivalents: Corporate debt securities $ 23,083 $ — $ 23,083 $ — Money market accounts 11,628 11,628 — — Total marketable securities and cash equivalents $ 34,711 $ 11,628 $ 23,083 $ — December 31, 2018 Total Level 1 Level 2 Level 3 (in thousands) Marketable securities and cash equivalents: Corporate debt securities $ 28,904 $ — $ 28,904 $ — United States Treasury 990 — 990 — U.S. government agency securities 790 — 790 — Money market accounts 2,692 2,692 — — Total marketable securities and cash equivalents $ 33,376 $ 2,692 $ 30,684 $ —

Fixed Assets (Tables)

Fixed Assets (Tables)	9 Months Ended
	Sep. 30, 2019
Property Plant And Equipment [Abstract]
Major Classes of Fixed Assets	Major classes of fixed assets consisted of the following: September 30, December 31, Useful Lives 2019 2018 (in thousands) Computer hardware 3 Years $ 1,702 $ 1,579 Computer software 3 Years 541 495 Medical lab equipment 5 Years 8,144 8,136 Furniture and fixtures 5 Years 234 233 Leasehold improvements Shorter of lease term or estimated useful life 815 802 Assets not yet placed in service 2,402 1,087 Total 13,838 12,332 Less: Accumulated depreciation (7,442 ) (5,886 ) Property and equipment, net $ 6,396 $ 6,446

Significant Balance Sheet Acc_2

Significant Balance Sheet Accounts (Tables)	9 Months Ended
	Sep. 30, 2019
Balance Sheet Related Disclosures [Abstract]
Schedule of Other Current Assets	Other current assets consisted of the following: September 30, 2019 December 31, 2018 (in thousands) Reagents $ 244 $ 314 Contract assets 150 150 Prepaid expenses 1,160 556 Prepaid income taxes 41 1,251 Marketable securities interest receivable 173 220 Other receivable 27 70 Total $ 1,795 $ 2,561

Reporting Segment and Geograp_2

Reporting Segment and Geographic Information (Tables)	9 Months Ended
	Sep. 30, 2019
Segment Reporting [Abstract]
Summary of Revenue by Geographic Region	Revenue by region during the three and nine months ended September 30, 2019 and 2018 were as follows: Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 (in thousands) Revenue: United States $ 8,479 $ 3,273 $ 18,779 $ 9,099 Foreign: Canada 548 1,120 1,602 3,160 Other Countries 1,320 1,232 3,760 3,419 Total $ 10,347 $ 5,625 $ 24,141 $ 15,678

Leases (Tables)

Leases (Tables)	9 Months Ended
	Sep. 30, 2019
Leases [Abstract]
Schedule of Operating Lease Expense	The following was operating lease expense: Three months ended September 30, 2019 Nine months ended September 30, 2019 Operating lease cost $ 146 $ 438
Schedule of Supplemental Cash Flow Information Related to Leases	Supplemental cash flow information related to leases was the following: Three months ended September 30, 2019 Nine months ended September 30, 2019 Cash paid for amounts included in the measurement of lease liabilities $ 140 $ 391 Noncash lease expense $ 105 $ 306 Right-of-use assets obtained in exchange for new operating lease liabilities $ 110 $ 110
Schedule of Supplemental Balance Sheet Information Related to Leases	Supplemental balance sheet information related to leases was the following: September 30, 2019 Weighted average remaining lease term - operating leases 5.8 years Weighted average discount rate - operating leases 6.25 %
Schedule of Maturity Analysis of Operating Lease Liabilities using Undiscounted Cash Flows on an Annual Basis	The following is a maturity analysis of operating lease liabilities using undiscounted cash flows on an annual basis with renewal periods included: Operating Leases (in thousands) Year Ending December 31, 2019 (remaining 3 months) $ 142 2020 575 2021 591 2022 597 2023 567 2024 330 Thereafter 532 Total lease payments 3,334 Less imputed interest (559 ) Total $ 2,775
Schedule of Future Minimum Payments for Noncancelable Operating Leases	Future minimum payments under non-cancelable operating leases as of December 31, 2018 are as follows: Amounts (in thousands) Year ending December 31, 2019 $ 560 2020 559 2021 550 2022 558 2023 567 Thereafter 862 Total minimum lease payments $ 3,656

Equity-Based Compensation (Tabl

Equity-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2019
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Summary of Equity-Based Compensation	The Company has included equity-based compensation expense as part of cost of revenue and operating expenses in the accompanying condensed consolidated statements of operations as follows: Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 (in thousands) Cost of revenue $ 174 $ 121 $ 483 $ 396 Research and development 279 214 690 517 Selling and marketing 332 115 643 336 General and administrative 166 138 455 457 Total $ 951 $ 588 $ 2,271 $ 1,706

Loss Per Share (Tables)

Loss Per Share (Tables)	9 Months Ended
	Sep. 30, 2019
Earnings Per Share [Abstract]
Reconciliation of the Basic and Diluted Loss Per Share Computations	The following table presents the calculation of basic and diluted loss per share Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 (in thousands, except per share data) Net income (loss) $ 1,462 $ (595 ) $ (115 ) $ (3,554 ) Weighted-average common shares—outstanding, basic 18,501 18,012 18,358 17,931 Weighted-average common shares—outstanding, diluted 19,456 18,012 18,358 17,931 Net income (loss) per common share, basic $ 0.08 $ (0.03 ) $ (0.01 ) $ (0.20 ) Net income (loss) per common share, diluted $ 0.08 $ (0.03 ) $ (0.01 ) $ (0.20 )
Anti-dilutive Securities Excluded from Calculation of Diluted Loss Per Share	The following securities have been excluded from the calculation of diluted loss per share because their effect would have been anti-dilutive: Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 (in thousands) Options 19 429 351 424 RSUs 20 1,045 1,056 914

Equity Method Investments (Tabl

Equity Method Investments (Tables)	9 Months Ended
	Sep. 30, 2019
Equity Method Investments And Joint Ventures [Abstract]
Schedule of Equity Method Investments	Equity method investments as of September 30 September 30, 2019 December 31, 2018 Carrying Value Ownership Percentage Carrying Value Ownership Percentage (in thousands) FF Gene Biotech $ 909 30 % $ 1,512 30 % Total equity method investments $ 909 30 % $ 1,512 30 %
Summary of Financial Information for Equity Method Investees	Summary Financial Information Summary financial information for FF Gene Biotech is as follows: Nine Months Ended September 30 2019 2018 Consolidated Statements of Operations Data: (in thousands) Net Sales $ 2,126 $ 577 Gross Profit 1,123 30 Net Loss (2,322 ) (2,327 ) Share of loss from investments accounted for using the equity method (603 ) (701 )

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Additional Information (Detail)	3 Months Ended		9 Months Ended
	Sep. 30, 2019USD ($)Customer	Sep. 30, 2018USD ($)Customer	Sep. 30, 2019USD ($)Customer	Sep. 30, 2018USD ($)Customer	Jan. 01, 2019USD ($)	Dec. 31, 2018USD ($)
Summary Of Significant Accounting Policies [Line Items]
Receivables from contract with customers	$ 5,292,000		$ 5,292,000			$ 5,948,000
Contract with customer liability, revenue recognized	48,000	$ 26,000	$ 37,000	$ 16,000
Practical expedient not to disclose amount of transaction price allocated to unsatisfied performance obligations			true
Operating lease liabilities	2,775,000		$ 2,775,000		$ 3,000,000
Right-of-use assets	2,739,000		2,739,000		$ 3,000,000
Other Current Assets
Summary Of Significant Accounting Policies [Line Items]
Contract assets from contract with customers	150,000		150,000			150,000
Accrued Liabilities
Summary Of Significant Accounting Policies [Line Items]
Contract liabilities from contract with customers	$ 369,000		$ 369,000			$ 166,000
Customer Concentration Risk | Revenue
Summary Of Significant Accounting Policies [Line Items]
Number of customers | Customer	1	1	1	1
Customer Concentration Risk | Revenue | Customer One
Summary Of Significant Accounting Policies [Line Items]
Concentration risk, percentage	40.00%	13.00%	33.00%	13.00%

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Summary of Revenue from Contracts with Customers by Payor Type (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Disaggregation Of Revenue [Line Items]
Revenue from contracts with customers by payor type	$ 10,347	$ 5,625	$ 24,141	$ 15,678
Accounting Standards Update 2014-09
Disaggregation Of Revenue [Line Items]
Type of Revenue [Extensible List]	flgt:GeneticTestingServicesMember	flgt:GeneticTestingServicesMember	flgt:GeneticTestingServicesMember	flgt:GeneticTestingServicesMember
Revenue from contracts with customers by payor type	$ 10,347	$ 5,625	$ 24,141	$ 15,678
Accounting Standards Update 2014-09 | Clinical Institutional Contracts
Disaggregation Of Revenue [Line Items]
Revenue from contracts with customers by payor type	10,031	5,334	23,310	14,594
Accounting Standards Update 2014-09 | Clinical Patient Contracts
Disaggregation Of Revenue [Line Items]
Revenue from contracts with customers by payor type	128	148	373	407
Accounting Standards Update 2014-09 | Clinical Insurance Contracts
Disaggregation Of Revenue [Line Items]
Revenue from contracts with customers by payor type	$ 188	$ 143	$ 458	$ 677

Marketable Securities - Summary

Marketable Securities - Summary of Marketable Securities (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Schedule of Available For Sale Securities [Line Items]
Marketable securities, Amortized Cost Basis	$ 22,923	$ 30,776
Marketable securities, Unrealized Gains	161	12
Marketable securities, Unrealized Losses	(1)	(104)
Marketable securities, Aggregate Fair Value	23,083	30,684
Cash and cash equivalents	20,522	6,736
Less: cash equivalents	(11,628)	(2,692)
Short-Term Marketable Securities
Schedule of Available For Sale Securities [Line Items]
Marketable securities, Amortized Cost Basis	11,569	24,393
Marketable securities, Unrealized Gains	28	1
Marketable securities, Unrealized Losses	(1)	(96)
Marketable securities, Aggregate Fair Value	11,596	24,298
Short-Term Marketable Securities | Corporate Debt Securities
Schedule of Available For Sale Securities [Line Items]
Marketable securities, Amortized Cost Basis	11,569	22,613
Marketable securities, Unrealized Gains	28	1
Marketable securities, Unrealized Losses	(1)	(96)
Marketable securities, Aggregate Fair Value	11,596	22,518
Short-Term Marketable Securities | United States Treasury
Schedule of Available For Sale Securities [Line Items]
Marketable securities, Amortized Cost Basis		990
Marketable securities, Aggregate Fair Value		990
Short-Term Marketable Securities | U.S. Government Agency Securities
Schedule of Available For Sale Securities [Line Items]
Marketable securities, Amortized Cost Basis		790
Marketable securities, Aggregate Fair Value		790
Long-Term Marketable Securities
Schedule of Available For Sale Securities [Line Items]
Marketable securities, Amortized Cost Basis	11,354	6,383
Marketable securities, Unrealized Gains	133	11
Marketable securities, Unrealized Losses		(8)
Marketable securities, Aggregate Fair Value	11,487	6,386
Long-Term Marketable Securities | Corporate Debt Securities
Schedule of Available For Sale Securities [Line Items]
Marketable securities, Amortized Cost Basis	11,354	6,383
Marketable securities, Unrealized Gains	133	11
Marketable securities, Unrealized Losses		(8)
Marketable securities, Aggregate Fair Value	11,487	6,386
Short Term Marketable Securities | Money Market Accounts
Schedule of Available For Sale Securities [Line Items]
Cash and cash equivalents	11,628	2,692
Cash and cash equivalents fair value disclosure	$ 11,628	$ 2,692

Marketable Securities - Additio

Marketable Securities - Additional Information (Details) - USD ($)	9 Months Ended	12 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Investments Debt And Equity Securities [Abstract]
Gross unrealized loss	$ 1,000	$ 104,000

Fair Value Measurements - Infor

Fair Value Measurements - Information about Financial Assets Measured at Fair Value on Recurring Basis Based on Three-Tier Fair Value Hierarchy (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities	$ 23,083	$ 30,684
Fair Value Measurements Recurring
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total marketable securities and cash equivalents	34,711	33,376
Fair Value Measurements Recurring | Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total marketable securities and cash equivalents	11,628	2,692
Fair Value Measurements Recurring | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total marketable securities and cash equivalents	23,083	30,684
Fair Value Measurements Recurring | Level 3
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total marketable securities and cash equivalents	0	0
Fair Value Measurements Recurring | Money Market Accounts
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash and cash equivalents fair value disclosure	11,628	2,692
Fair Value Measurements Recurring | Money Market Accounts | Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash and cash equivalents fair value disclosure	11,628	2,692
Fair Value Measurements Recurring | Money Market Accounts | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash and cash equivalents fair value disclosure	0	0
Fair Value Measurements Recurring | Money Market Accounts | Level 3
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash and cash equivalents fair value disclosure	0	0
Fair Value Measurements Recurring | Corporate Debt Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities	23,083	28,904
Fair Value Measurements Recurring | Corporate Debt Securities | Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities	0	0
Fair Value Measurements Recurring | Corporate Debt Securities | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities	23,083	28,904
Fair Value Measurements Recurring | Corporate Debt Securities | Level 3
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities	$ 0	0
Fair Value Measurements Recurring | United States Treasury
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities		990
Fair Value Measurements Recurring | United States Treasury | Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities		0
Fair Value Measurements Recurring | United States Treasury | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities		990
Fair Value Measurements Recurring | United States Treasury | Level 3
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities		0
Fair Value Measurements Recurring | U.S. Government Agency Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities		790
Fair Value Measurements Recurring | U.S. Government Agency Securities | Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities		0
Fair Value Measurements Recurring | U.S. Government Agency Securities | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities		790
Fair Value Measurements Recurring | U.S. Government Agency Securities | Level 3
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities		$ 0

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Details)	3 Months Ended
	Sep. 30, 2019USD ($)
Fair Value Disclosures [Abstract]
Fair value asset, investments measured using unobservable inputs	$ 0
Fair value assets, transfers between levels, amount	0
Unrealized losses for securities in an unrealized loss position for more than 12 months	1,000
Other-than-temporary impairment losses related to marketable securities	$ 0

Fixed Assets - Major Classes of

Fixed Assets - Major Classes of Fixed Assets (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Property Plant And Equipment [Line Items]
Fixed assets, gross	$ 13,838	$ 12,332
Less: Accumulated depreciation	(7,442)	(5,886)
Fixed assets, net	6,396	6,446
Computer Hardware
Property Plant And Equipment [Line Items]
Fixed assets, gross	$ 1,702	1,579
Useful life in years	3 years
Computer Software
Property Plant And Equipment [Line Items]
Fixed assets, gross	$ 541	495
Useful life in years	3 years
Medical Lab Equipment
Property Plant And Equipment [Line Items]
Fixed assets, gross	$ 8,144	8,136
Useful life in years	5 years
Furniture and Fixtures
Property Plant And Equipment [Line Items]
Fixed assets, gross	$ 234	233
Useful life in years	5 years
Leasehold Improvements
Property Plant And Equipment [Line Items]
Fixed assets, gross	$ 815	802
Useful life in years	Shorter of lease term or estimated useful life
Assets Not Yet Placed in Service
Property Plant And Equipment [Line Items]
Fixed assets, gross	$ 2,402	$ 1,087

Fixed Assets - Additional Infor

Fixed Assets - Additional Information (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Property Plant And Equipment [Abstract]
Depreciation expense on fixed assets	$ 503,000	$ 547,000	$ 1,549,000	$ 1,625,000

Significant Balance Sheet Acc_3

Significant Balance Sheet Accounts - Schedule of Other Current Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Balance Sheet Related Disclosures [Abstract]
Reagents	$ 244	$ 314
Contract assets	150	150
Prepaid expenses	1,160	556
Prepaid income taxes	41	1,251
Marketable securities interest receivable	173	220
Other receivable	27	70
Total	$ 1,795	$ 2,561

Reporting Segment and Geograp_3

Reporting Segment and Geographical Information - Additional Information (Details)	9 Months Ended
	Sep. 30, 2019Segment
Segment Reporting [Abstract]
Number of reporting segments	1

Reporting Segment and Geograp_4

Reporting Segment and Geographical Information - Summary of Revenue by Geographic Region (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Segment Reporting Information [Line Items]
Revenue	$ 10,347	$ 5,625	$ 24,141	$ 15,678
United States
Segment Reporting Information [Line Items]
Revenue	8,479	3,273	18,779	9,099
Canada
Segment Reporting Information [Line Items]
Revenue	548	1,120	1,602	3,160
Other Countries
Segment Reporting Information [Line Items]
Revenue	$ 1,320	$ 1,232	$ 3,760	$ 3,419

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details) - Reagents $ in Millions	Sep. 30, 2019USD ($)
Commitments And Contingencies [Line Items]
Non-cancelable purchase obligations	$ 3.7
Non-cancelable purchase obligations, payable within next twenty-four months	542,000
Non-cancelable purchase obligations, payable within twelve months	$ 3.1

Leases - Additional Information

Leases - Additional Information (Details) - USD ($)	Sep. 01, 2019	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Jan. 01, 2019
Lessee Lease Description [Line Items]
Operating leases term of expiration				2023-08
Operating leases, renewal term		3 years		3 years
Rent expense, including sublease		$ 140,000	$ 70,000	$ 405,000	$ 298,000
Long-term ROU assets		2,739,000		2,739,000		$ 3,000,000
Short-term lease liabilities		409,000		409,000		384,000
Long-term lease liabilities		$ 2,366,000		2,366,000		$ 2,600,000
Impact to retained earnings upon adoption ASC 842				$ 0
Georgia
Lessee Lease Description [Line Items]
Long-term ROU assets	$ 110,000
Short-term lease liabilities	23,000
Long-term lease liabilities	$ 87,000
Lease termination date	August 31, 2019

Leases - Schedule of Operating

Leases - Schedule of Operating Lease Expense (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019
Leases [Abstract]
Operating lease cost	$ 146	$ 438

Leases - Schedule of Supplement

Leases - Schedule of Supplemental Cash Flow Information Related to Leases (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019
Leases [Abstract]
Cash paid for amounts included in the measurement of lease liabilities	$ 140	$ 391
Noncash lease expense	105	306
Right-of-use assets obtained in exchange for new operating lease liabilities	$ 110	$ 110

Leases - Schedule of Suppleme_2

Leases - Schedule of Supplemental Balance Sheet Information Related to Leases (Details)	Sep. 30, 2019
Leases [Abstract]
Weighted average remaining lease term - operating leases	5 years 9 months 18 days
Weighted average discount rate - operating leases	6.25%

Leases - Schedule of Maturity A

Leases - Schedule of Maturity Analysis of Operating Lease Liabilities using Undiscounted Cash Flows on an Annual Basis (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Jan. 01, 2019
Leases [Abstract]
2019 (remaining 3 months)	$ 142
2020	575
2021	591
2022	597
2023	567
2024	330
Thereafter	532
Total lease payments	3,334
Less imputed interest	(559)
Total	$ 2,775	$ 3,000

Leases - Schedule of Future Min

Leases - Schedule of Future Minimum Payments for Noncancelable Operating Leases (Detail) $ in Thousands	Dec. 31, 2018USD ($)
Leases [Abstract]
2019	$ 560
2020	559
2021	550
2022	558
2023	567
Thereafter	862
Total minimum lease payments	$ 3,656

Equity-Based Compensation - Sum

Equity-Based Compensation - Summary of Equity-Based Compensation Expenses as Part of Cost of Revenue and Operating Expenses (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Equity-based compensation expense	$ 951	$ 588	$ 2,271	$ 1,706
Cost of Revenue
Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Equity-based compensation expense	174	121	483	396
Research and Development
Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Equity-based compensation expense	279	214	690	517
Selling and Marketing
Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Equity-based compensation expense	332	115	643	336
General and Administrative
Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Equity-based compensation expense	$ 166	$ 138	$ 455	$ 457

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Income Tax Disclosure [Abstract]
Effective income tax rate	4.00%	45.00%	14.00%	23.00%

Loss per Share - Reconciliation

Loss per Share - Reconciliation of Basic and Diluted Loss Per Share Computations (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018
Earnings Per Share [Abstract]
Net income (loss)	$ 1,462	$ 331	$ (1,908)	$ (595)	$ (1,049)	$ (1,910)	$ (115)	$ (3,554)
Weighted-average common shares—outstanding, basic	18,501			18,012			18,358	17,931
Weighted-average common shares—outstanding, diluted	19,456			18,012			18,358	17,931
Net income (loss) per common share, basic	$ 0.08			$ (0.03)			$ (0.01)	$ (0.20)
Net income (loss) per common share, diluted	$ 0.08			$ (0.03)			$ (0.01)	$ (0.20)

Loss per Share - Anti-dilutive

Loss per Share - Anti-dilutive Securities Excluded from Calculation of Diluted Loss Per Share (Details) - shares shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Options
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from calculation of diluted loss per share	19	429	351	424
Restricted Stock Units (RSUs)
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from calculation of diluted loss per share	20	1,045	1,056	914

Related Party - Additional Info

Related Party - Additional Information (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018	Apr. 30, 2017
Related Party Transaction [Line Items]
Ownership percentage	30.00%		30.00%		30.00%
Xilong Scientific
Related Party Transaction [Line Items]
Ownership percentage of common stock outstanding shares	11.00%		11.00%
Foundation
Related Party Transaction [Line Items]
Revenue from related parties	$ 0	$ 16,000	$ 16,000	$ 24,000
Due from related parties	2,500		2,500		$ 0
Foundation | Research Testing Services
Related Party Transaction [Line Items]
Revenue from related parties	0	0	2,500	0
University
Related Party Transaction [Line Items]
Revenue from related parties	29,000	$ 37,000	51,000	$ 53,000
Due from related parties	$ 37,000		$ 37,000		51,000
FF Gene Biotech | FJIP
Related Party Transaction [Line Items]
Ownership percentage						19.00%
FF Gene Biotech | Dr. Han Lin Gao | FJIP
Related Party Transaction [Line Items]
Ownership percentage	25.00%		25.00%
Fulgent Pharma
Related Party Transaction [Line Items]
Due from related parties	$ 29,000		$ 29,000		$ 22,000

Equity Method Investments - Add

Equity Method Investments - Additional Information (Details)	1 Months Ended	3 Months Ended		9 Months Ended
	Apr. 30, 2017CNY (¥)	Sep. 30, 2019USD ($)	Sep. 30, 2018USD ($)	Sep. 30, 2019USD ($)	Sep. 30, 2018USD ($)	Sep. 30, 2019CNY (¥)	Dec. 31, 2018
Schedule Of Equity Method Investments [Line Items]
Ownership interest to be made in joint venture		30.00%		30.00%		30.00%	30.00%
Royalty earned | $		$ 10,347,000	$ 5,625,000	$ 24,141,000	$ 15,678,000
Royalty | License Agreement
Schedule Of Equity Method Investments [Line Items]
Royalty earned | $			$ 12,000		$ 47,000
FF Gene Biotech
Schedule Of Equity Method Investments [Line Items]
Contribution to be made in joint venture | ¥	¥ 60,000,000
Contribution period in joint venture	5 years
Previous contribution period in joint venture	3 years
Ownership interest to be made in joint venture	30.00%	30.00%		30.00%		30.00%	30.00%
Contributions remain for joint venture		$ 5,700,000		$ 5,700,000		¥ 40,300,000
FF Gene Biotech | Equipment
Schedule Of Equity Method Investments [Line Items]
Contributions made to joint venture | $				$ 3,000,000
Xilong Scientific | FF Gene Biotech
Schedule Of Equity Method Investments [Line Items]
Contribution to be made in joint venture | ¥	¥ 102,000,000
Contribution period in joint venture	5 years
Previous contribution period in joint venture	3 years
Ownership interest to be made in joint venture	51.00%
FJIP | FF Gene Biotech
Schedule Of Equity Method Investments [Line Items]
Contribution to be made in joint venture | ¥	¥ 19,000,000
Contribution period in joint venture	10 years
Previous contribution period in joint venture	5 years
Ownership interest to be made in joint venture	19.00%

Equity Method Investments - Sch

Equity Method Investments - Schedule of Equity Method Investments (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018	Apr. 30, 2017
Schedule Of Equity Method Investments [Line Items]
Carrying Value	$ 909	$ 1,512
Ownership percentage	30.00%	30.00%
FF Gene Biotech
Schedule Of Equity Method Investments [Line Items]
Carrying Value	$ 909	$ 1,512
Ownership percentage	30.00%	30.00%	30.00%

Equity Method Investments - Sum

Equity Method Investments - Summary of Financial Information for Equity Method Investees, Statement of Operations Data (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Schedule Of Equity Method Investments [Line Items]
Equity loss in investee	$ (175)	$ (210)	$ (603)	$ (701)
FF Gene Biotech
Schedule Of Equity Method Investments [Line Items]
Net Sales			2,126	577
Gross Profit			1,123	30
Net Loss			(2,322)	(2,327)
Equity loss in investee			$ (603)	$ (701)

Equity Distribution Agreement -

Equity Distribution Agreement - Additional Information (Detail) - Equity Distribution Agreement - Common Stock - USD ($)	1 Months Ended	3 Months Ended
	Aug. 31, 2019	Sep. 30, 2019
Equity Distribution Agreement [Line Items]
Number of shares sold		104,390
Sale of stock, weighted average selling price per share		$ 12.14
Net proceeds from sale of stock		$ 979,000
Maximum
Equity Distribution Agreement [Line Items]
Aggregate offering price	$ 30,000,000
Percentage of commission to be paid from gross proceeds	3.00%