Condensed Consolidated Statements of Changes in Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Deficit	Accumulated Other Comprehensive Loss
Beginning balance (in shares) at Dec. 31, 2018		38,466
Beginning balance at Dec. 31, 2018	$ 71,002	$ 385	$ 239,865	$ (168,140)	$ (1,108)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) income	9,949			9,949
Other comprehensive income (loss)	56				56
Stock option exercises and employee stock plan purchases (in shares)		37
Stock option exercises and employee stock plan purchases	606		606
Vesting of restricted stock awards and units (in shares)		365
Vesting of restricted stock awards and units	0	$ 4	(4)
Shares withheld to cover taxes (in shares)		(50)
Shares withheld to cover taxes	(1,120)	$ (1)	(1,119)
Stock-based compensation	2,720		2,720
Ending balance (in shares) at Mar. 31, 2019		38,818
Ending balance at Mar. 31, 2019	83,213	$ 388	242,068	(158,191)	(1,052)
Beginning balance (in shares) at Dec. 31, 2018		38,466
Beginning balance at Dec. 31, 2018	71,002	$ 385	239,865	(168,140)	(1,108)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) income	21,217
Other comprehensive income (loss)	111
Ending balance (in shares) at Sep. 30, 2019		39,229
Ending balance at Sep. 30, 2019	101,166	$ 392	248,694	(146,923)	(997)
Beginning balance (in shares) at Mar. 31, 2019		38,818
Beginning balance at Mar. 31, 2019	83,213	$ 388	242,068	(158,191)	(1,052)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) income	6,412			6,412
Other comprehensive income (loss)	88				88
Stock option exercises and employee stock plan purchases (in shares)		9
Stock option exercises and employee stock plan purchases	120		120
Vesting of restricted stock awards and units (in shares)		253
Vesting of restricted stock awards and units	0	$ 3	(3)
Shares withheld to cover taxes (in shares)		(37)
Shares withheld to cover taxes	(944)	$ (1)	(943)
Stock-based compensation	3,358		3,358
Ending balance (in shares) at Jun. 30, 2019		39,043
Ending balance at Jun. 30, 2019	92,247	$ 390	244,600	(151,779)	(964)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) income	4,856			4,856
Other comprehensive income (loss)	(33)				(33)
Stock option exercises and employee stock plan purchases (in shares)		49
Stock option exercises and employee stock plan purchases	1,020	$ 1	1,019
Vesting of restricted stock awards and units (in shares)		153
Vesting of restricted stock awards and units	0	$ 2	(2)
Shares withheld to cover taxes (in shares)		(16)
Shares withheld to cover taxes	(347)	$ (1)	(346)
Stock-based compensation	3,423		3,423
Ending balance (in shares) at Sep. 30, 2019		39,229
Ending balance at Sep. 30, 2019	101,166	$ 392	248,694	(146,923)	(997)
Beginning balance (in shares) at Dec. 31, 2019		39,251
Beginning balance at Dec. 31, 2019	114,601	$ 393	251,641	(136,473)	(960)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) income	3,337			3,337
Other comprehensive income (loss)	(1,434)				(1,434)
Stock option exercises and employee stock plan purchases (in shares)		33
Stock option exercises and employee stock plan purchases	366		366
Vesting of restricted stock awards and units (in shares)		563
Vesting of restricted stock awards and units	0	$ 6	(6)
Shares withheld to cover taxes (in shares)		(97)
Shares withheld to cover taxes	(1,547)	$ (1)	(1,546)
Stock-based compensation	3,075		3,075
Ending balance (in shares) at Mar. 31, 2020		39,750
Ending balance at Mar. 31, 2020	118,398	$ 398	253,530	(133,136)	(2,394)
Beginning balance (in shares) at Dec. 31, 2019		39,251
Beginning balance at Dec. 31, 2019	114,601	$ 393	251,641	(136,473)	(960)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) income	(10,061)
Other comprehensive income (loss)	(1,550)
Ending balance (in shares) at Sep. 30, 2020		66,850
Ending balance at Sep. 30, 2020	513,579	$ 668	661,955	(146,534)	(2,510)
Beginning balance (in shares) at Mar. 31, 2020		39,750
Beginning balance at Mar. 31, 2020	118,398	$ 398	253,530	(133,136)	(2,394)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) income	(7,012)			(7,012)
Other comprehensive income (loss)	(212)				(212)
Stock option exercises and employee stock plan purchases (in shares)		7
Stock option exercises and employee stock plan purchases	50		50
Vesting of restricted stock awards and units (in shares)		242
Vesting of restricted stock awards and units	0	$ 2	(2)
Shares withheld to cover taxes (in shares)		(36)
Shares withheld to cover taxes	(485)	$ (1)	(484)
Issuance of common stock (in shares)		26,845
Issuance of common stock, net of $3,776 issuance costs	394,334	$ 269	394,065
Fair value of replacement options related to pre-acquisition services	7,125		7,125
Stock-based compensation	3,385		3,385
Ending balance (in shares) at Jun. 30, 2020		66,808
Ending balance at Jun. 30, 2020	515,583	$ 668	657,669	(140,148)	(2,606)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) income	(6,386)			(6,386)
Other comprehensive income (loss)	96				96
Stock option exercises and employee stock plan purchases (in shares)		32
Stock option exercises and employee stock plan purchases	344		344
Vesting of restricted stock awards and units (in shares)		13
Vesting of restricted stock awards and units	0	$ 1	(1)
Shares withheld to cover taxes (in shares)		(3)
Shares withheld to cover taxes	(50)	$ (1)	(49)
Stock-based compensation	3,992		3,992
Ending balance (in shares) at Sep. 30, 2020		66,850
Ending balance at Sep. 30, 2020	$ 513,579	$ 668	$ 661,955	$ (146,534)	$ (2,510)