CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS EQUITY - USD ($) $ in Thousands	Total	Common Stock and Additional Paid-In Capital	Accumulated Other Comprehensive Income	Accumulated Deficit	Treasury Stock
Beginning balance (in shares) at Dec. 31, 2018		37,652,498			6,823,147
Beginning balance at Dec. 31, 2018	$ 99,660	$ 246,415	$ 116	$ (98,521)	$ (48,350)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(19,636)			(19,636)
Unrealized gain (loss) on available-for-sale securities, net of taxes	22		22
Issuance of common stock for employee stock purchase (in shares)		13,479
Issuance of common stock for employee stock purchase	109	$ 109
Exercise of stock options, net of shares withheld for employee taxes (in shares)		61,798
Exercise of stock options, net of shares withheld for employee taxes	371	$ 371
Release of restricted stock units and awards (in shares)		760,552
Release of restricted stock units and awards	0
Stock-based compensation	3,184	$ 3,184
Ending balance (in shares) at Jun. 30, 2019		38,488,327			6,823,147
Ending balance at Jun. 30, 2019	83,710	$ 250,079	138	(118,157)	$ (48,350)
Beginning balance (in shares) at Mar. 31, 2019		38,375,744			6,823,147
Beginning balance at Mar. 31, 2019	90,933	$ 248,698	122	(109,537)	$ (48,350)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(8,620)			(8,620)
Unrealized gain (loss) on available-for-sale securities, net of taxes	16		16
Exercise of stock options, net of shares withheld for employee taxes (in shares)		50,027
Exercise of stock options, net of shares withheld for employee taxes	300	$ 300
Release of restricted stock units and awards (in shares)		62,556
Release of restricted stock units and awards	0
Stock-based compensation	1,081	$ 1,081
Ending balance (in shares) at Jun. 30, 2019		38,488,327			6,823,147
Ending balance at Jun. 30, 2019	83,710	$ 250,079	138	(118,157)	$ (48,350)
Beginning balance (in shares) at Dec. 31, 2019		38,624,784			7,210,456
Beginning balance at Dec. 31, 2019	83,757	$ 253,289	124	(118,565)	$ (51,091)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(5,540)			(5,540)
Unrealized gain (loss) on available-for-sale securities, net of taxes	(2)		(2)
Repurchased shares (in shares)					4,932,977
Stock repurchases	(30,642)				$ (30,642)
Issuance of common stock for employee stock purchase (in shares)		10,162
Issuance of common stock for employee stock purchase	63	$ 63
Release of restricted stock units and awards (in shares)		372,630
Stock-based compensation	2,094	$ 2,094
Ending balance (in shares) at Jun. 30, 2020		39,007,576			12,143,433
Ending balance at Jun. 30, 2020	49,730	$ 255,446	122	(124,105)	$ (81,733)
Beginning balance (in shares) at Mar. 31, 2020		38,824,681			9,223,222
Beginning balance at Mar. 31, 2020	67,744	$ 254,081	122	(123,393)	$ (63,066)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(712)			(712)
Unrealized gain (loss) on available-for-sale securities, net of taxes	0
Repurchased shares (in shares)					2,920,211
Stock repurchases	(18,667)				$ (18,667)
Release of restricted stock units and awards (in shares)		182,895
Release of restricted stock units and awards	0
Stock-based compensation	1,365	$ 1,365
Ending balance (in shares) at Jun. 30, 2020		39,007,576			12,143,433
Ending balance at Jun. 30, 2020	$ 49,730	$ 255,446	$ 122	$ (124,105)	$ (81,733)