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 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	$ 0	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, 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 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)