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, 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 income (loss)	(5,540)			(5,540)
Unrealized gain on available-for-sale securities, net of taxes	(2)		(2)
Issuance of common stock for employee stock purchase (in shares)		10,162
Issuance of stock for ESPP purchases	$ 63	$ 63
Repurchased shares (in shares)	4,900,000				4,932,977
Repurchase of stock	$ (30,642)				$ (30,642)
Release of restricted stock units and awards (in shares)		372,630
Release of restricted stock units and awards	0
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 income (loss)	(712)			(712)
Unrealized gain on available-for-sale securities, net of taxes	$ 0
Repurchased shares (in shares)	2,900,000				2,920,211
Repurchase of stock	$ (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)
Beginning balance (in shares) at Dec. 31, 2020		39,161,214			12,143,433
Beginning balance at Dec. 31, 2020	63,981	$ 258,756	122	(113,164)	$ (81,733)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	7,377			7,377
Unrealized gain on available-for-sale securities, net of taxes	0
Issuance of common stock for employee stock purchase (in shares)		15,543
Issuance of stock for ESPP purchases	89	$ 89
Exercise of stock options, net of shares withheld for employee taxes (in shares)		325,737
Exercise of stock options, net of shares withheld for employee taxes	2,864	$ 2,864
Release of restricted stock units and awards (in shares)		440,365
Release of restricted stock units and awards	0
Stock Issued During Period, Value, New Issues	35,833	$ 35,833
Stock Issued During Period, Shares, New Issues		3,309,811
Stock-based compensation	1,582	$ 1,582
Ending balance (in shares) at Jun. 30, 2021		43,252,670			12,143,433
Ending balance at Jun. 30, 2021	111,726	$ 299,124	122	(105,787)	$ (81,733)
Beginning balance (in shares) at Mar. 31, 2021		43,020,610			12,143,433
Beginning balance at Mar. 31, 2021	105,298	$ 298,037	122	(111,128)	$ (81,733)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	5,341			5,341
Unrealized gain on available-for-sale securities, net of taxes	0
Exercise of stock options, net of shares withheld for employee taxes (in shares)		18,750
Exercise of stock options, net of shares withheld for employee taxes	140	$ 140
Release of restricted stock units and awards (in shares)		213,310
Release of restricted stock units and awards	0
Stock Issued During Period, Value, New Issues	(104)	$ (104)
Stock-based compensation	1,051	$ 1,051
Ending balance (in shares) at Jun. 30, 2021		43,252,670			12,143,433
Ending balance at Jun. 30, 2021	$ 111,726	$ 299,124	$ 122	$ (105,787)	$ (81,733)