CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Comprehensive Income	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Treasury Stock
Balance at Dec. 31, 2013	$ 87,008		$ 126	$ 907,148	$ (807,533)	$ (12,733)
Balance (in shares) at Dec. 31, 2013			12,620,000			1,369,000
Increase (Decrease) in Stockholders' Equity
Net income and comprehensive income	9,362	$ 9,362			9,362
Non-cash compensation	7,446			7,446
Purchase of treasury stock	$ (2,610)					$ (2,610)
Purchase of treasury stock (in shares)	99,345					99,000
Dividends	$ (28)			(28)
Issuance of common stock for stock options, restricted stock awards and restricted stock units, net of withholding taxes	(4,812)		$ 3	(4,815)
Issuance of common stock for stock options, restricted stock awards and restricted stock units, net of withholding taxes (in shares)			235,000
Balance at Dec. 31, 2014	96,366		$ 129	909,751	(798,171)	$ (15,343)
Balance (in shares) at Dec. 31, 2014			12,855,000			1,468,000
Increase (Decrease) in Stockholders' Equity
Net income and comprehensive income	48,047	48,047			48,047
Non-cash compensation	8,508			8,508
Purchase of treasury stock	$ (218)					$ (218)
Purchase of treasury stock (in shares)	5,250					6,000
Dividends	$ (11)			(11)
Issuance of common stock for stock options, restricted stock awards and restricted stock units, net of withholding taxes	(7,613)		$ 1	(7,614)
Issuance of common stock for stock options, restricted stock awards and restricted stock units, net of withholding taxes (in shares)			158,000
Tax benefit from stock-based award activity	4,601			4,601
Proceeds from equity offering, net of offering costs	91,462		$ 9	91,453
Issuance of stock for equity offering (in shares)			853,000
Balance at Dec. 31, 2015	241,142		$ 139	1,006,688	(750,124)	$ (15,561)
Balance (in shares) at Dec. 31, 2015			13,866,000			1,474,000
Increase (Decrease) in Stockholders' Equity
Net income and comprehensive income	27,494	$ 27,494			27,494
Non-cash compensation	9,647			9,647
Purchase of treasury stock	$ (48,524)					$ (48,524)
Purchase of treasury stock (in shares)	690,218					690,000
Issuance of common stock for stock options, restricted stock awards and restricted stock units, net of withholding taxes	$ (4,084)		$ 1	(4,085)
Issuance of common stock for stock options, restricted stock awards and restricted stock units, net of withholding taxes (in shares)			89,000
Tax benefit from stock-based award activity	5,760			5,760
Balance at Dec. 31, 2016	$ 231,435		$ 140	$ 1,018,010	$ (722,630)	$ (64,085)
Balance (in shares) at Dec. 31, 2016			13,955,000			2,164,000