CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS’ EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Accumulated Other Comprehensive Loss
Balance (in shares) at Dec. 31, 2018		74,697,526
Balance at Dec. 31, 2018	$ 197,221	$ 75	$ 419,456	$ (220,276)	$ (2,034)
Increase (Decrease) in Stockholders' Equity
Stock-based compensation expense	5,290		5,290
Exercise of stock options (in shares)		157,334
Exercise of stock options	703		703
Issuance of common stock for vested restricted stock awards (in shares)		1,372,723
Issuance of common stock for vested restricted stock awards	0	$ 2	(2)
Restricted stock awards withheld to cover taxes	(371)		(371)
Other comprehensive income	95				95
Net income	3,462			3,462
Balance (in shares) at Jun. 30, 2019		76,227,583
Balance at Jun. 30, 2019	206,400	$ 77	425,076	(216,814)	(1,939)
Balance (in shares) at Mar. 31, 2019		75,270,035
Balance at Mar. 31, 2019	201,227	$ 76	422,472	(219,018)	(2,303)
Increase (Decrease) in Stockholders' Equity
Stock-based compensation expense	2,865		2,865
Exercise of stock options (in shares)		5,597
Exercise of stock options	23		23
Issuance of common stock for vested restricted stock awards (in shares)		951,951
Issuance of common stock for vested restricted stock awards	0	$ 1	(1)
Restricted stock awards withheld to cover taxes	(283)		(283)
Other comprehensive income	364				364
Net income	2,204			2,204
Balance (in shares) at Jun. 30, 2019		76,227,583
Balance at Jun. 30, 2019	206,400	$ 77	425,076	(216,814)	(1,939)
Increase (Decrease) in Stockholders' Equity
Cumulative effect of new accounting principle in period of adoption | ASU 2016-13	(159)			(159)
Balance (in shares) at Dec. 31, 2019		70,756,013
Balance at Dec. 31, 2019	197,240	$ 71	430,959	(231,441)	(2,349)
Increase (Decrease) in Stockholders' Equity
Stock-based compensation expense	$ 6,035		6,035
Exercise of stock options (in shares)	506,105	506,105
Exercise of stock options	$ 1,987		1,987
Issuance of common stock for vested restricted stock awards (in shares)		1,543,388
Issuance of common stock for vested restricted stock awards	2	$ 2
Restricted stock awards withheld to cover taxes	(636)		(636)
Repurchase and retirement of common stock (in shares)		(12,935)
Repurchase and retirement of common stock	(65)			(65)
Other comprehensive income	666				666
Net income	7,971			7,971
Balance (in shares) at Jun. 30, 2020		72,792,571
Balance at Jun. 30, 2020	213,041	$ 73	438,345	(223,694)	(1,683)
Balance (in shares) at Mar. 31, 2020		71,185,492
Balance at Mar. 31, 2020	198,089	$ 71	434,622	(234,073)	(2,531)
Increase (Decrease) in Stockholders' Equity
Stock-based compensation expense	2,850		2,850
Exercise of stock options (in shares)		343,264
Exercise of stock options	1,423		1,423
Issuance of common stock for vested restricted stock awards (in shares)		1,263,815
Issuance of common stock for vested restricted stock awards	2	$ 2
Restricted stock awards withheld to cover taxes	(550)		(550)
Other comprehensive income	848				848
Net income	10,379			10,379
Balance (in shares) at Jun. 30, 2020		72,792,571
Balance at Jun. 30, 2020	$ 213,041	$ 73	$ 438,345	$ (223,694)	$ (1,683)