Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Convertible preferred stock	Preferred stock	Preferred stock Convertible preferred stock	Common stock	Additional paid-in capital	Accumulated other comprehensive income (loss)	Accumulated deficit	IPO	IPO Common stock	IPO Additional paid-in capital	Follow-on public offering	Follow-on public offering Common stock	Follow-on public offering Additional paid-in capital
Preferred stock, shares outstanding, beginning balance (in shares) at Dec. 31, 2016			0	19,837,000
Preferred stock, beginning balance at Dec. 31, 2016			$ 0
Common stock, shares outstanding, beginning balance (in shares) at Dec. 31, 2016					2,539,000
Beginning balance at Dec. 31, 2016	$ 29,691			$ 10	$ 1	$ 153,195	$ (3,009)	$ (120,506)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	1,837							1,837
Issuance of stock (in shares)				4,805,000
Issuance of stock	27,481			$ 2		27,479
Deferred offering costs						(721)
Exercise of stock options (in shares)					440,000
Exercise of stock options	336				$ 1	335
Stock-based compensation	369					369
Cumulative translation adjustment, net of tax	2,290						2,290
Preferred stock, shares outstanding, ending balance (in shares) at Dec. 31, 2017			0	24,642,000
Preferred stock, ending balance at Dec. 31, 2017			$ 0
Common stock, shares outstanding, ending balance (in shares) at Dec. 31, 2017					2,979,000
Ending balance at Dec. 31, 2017	61,283			$ 12	$ 2	180,657	(719)	(118,669)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	13,938							13,938
Conversion of convertible preferred stock to common stock (in shares)				(24,642,000)	24,642,000
Conversion of convertible preferred stock to common stock				$ (12)	$ 12
Issuance of stock (in shares)										6,900,000			1,520,000
Issuance of stock									$ 100,948	$ 1	$ 100,947	$ 37,885	$ 0	$ 37,885
Issuance of common stock pursuant to exercise of warrants (in shares)					160,000
Exercise of stock options (in shares)					387,000
Exercise of stock options	362				$ 0	362
Issuance of common stock pursuant to vesting of restricted stock awards and units, net of stock withheld for tax (in shares)					117,000
Stock-based compensation	4,805					4,805
Cumulative translation adjustment, net of tax	$ (1,438)						(1,438)
Preferred stock, shares outstanding, ending balance (in shares) at Dec. 31, 2018	0	0	0	0
Preferred stock, ending balance at Dec. 31, 2018			$ 0
Common stock, shares outstanding, ending balance (in shares) at Dec. 31, 2018	36,705,000				36,705,000
Ending balance at Dec. 31, 2018	$ 217,783			$ 0	$ 15	324,656	(2,157)	(104,731)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	$ (12,884)							(12,884)
Exercise of stock options (in shares)	867,000				868,000
Exercise of stock options	$ 1,560					1,560
Issuance of common stock pursuant to vesting of restricted stock awards and units, net of stock withheld for tax (in shares)					428,000
Issuance of common stock pursuant to vesting of restricted stock awards and units, net of stock withheld for tax	$ (524)					(524)
Issuance of common stock under the Employee Stock Purchase Plan (in shares)	83,000				83,000
Issuance of common stock under the Employee Stock Purchase Plan	$ 1,471					1,471
Stock-based compensation	9,730					9,730
Cumulative translation adjustment, net of tax	$ (528)						(528)
Preferred stock, shares outstanding, ending balance (in shares) at Dec. 31, 2019	0		0	0
Preferred stock, ending balance at Dec. 31, 2019			$ 0
Common stock, shares outstanding, ending balance (in shares) at Dec. 31, 2019	38,084,000				38,084,000
Ending balance at Dec. 31, 2019	$ 216,608			$ 0	$ 15	$ 336,732	$ (2,685)	$ (117,454)