Consolidated Statements of Stockholders' Equity (USD $) In Thousands, except Share data, unless otherwise specified	Total	Common Stock	Additional Paid-in Capital	Treasury Stock	Accumulated Other Comprehensive Income (Loss)	Retained Earnings
Beginning Balance at Dec. 31, 2011	$ 82,455	$ 1	$ 101,597	$ (47,207)	$ (81)	$ 28,145
Beginning Balance, Shares at Dec. 31, 2011		55,696,608		9,556,183
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock options exercised and RSUs vested, net of withholdings	1,929		1,929
Stock options exercised and RSUs vested, net of withholdings, Shares		881,390
Stock-based compensation	3,422		3,422
Excess tax benefit from stock-based compensation	4,713		4,713
Purchase of treasury stock	(19,996)			(19,996)
Purchase of treasury stock, Shares		(3,807,606)		(3,807,606)
Net income	14,738					14,738
Foreign currency translation adjustments	24				24
Ending Balance at Dec. 31, 2012	87,285	1	111,661	(67,203)	(57)	42,883
Ending Balance, Shares at Dec. 31, 2012		52,770,392		13,363,789
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock options exercised and RSUs vested, net of withholdings	15,048		15,048
Stock options exercised and RSUs vested, net of withholdings, Shares		2,896,072
Stock-based compensation	4,340		4,340
Excess tax benefit from stock-based compensation	6,797		6,797
Purchase of treasury stock	(25,000)			(25,000)
Purchase of treasury stock, Shares		(3,048,966)		(3,048,966)
Shares issued related to business acquisition	1,578		1,578
Shares issued related to business acquisition, Shares		107,749
Net income	18,244					18,244
Foreign currency translation adjustments	55				55
Ending Balance at Dec. 31, 2013	108,347	1	139,424	(92,203)	(2)	61,127
Ending Balance, Shares at Dec. 31, 2013		52,725,247		16,412,755
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock options exercised and RSUs vested, net of withholdings	9,653		9,653
Stock options exercised and RSUs vested, net of withholdings, Shares		2,002,823
Stock-based compensation	5,579		5,579
Excess tax benefit from stock-based compensation	7,985		7,985
Purchase of treasury stock	(22,442)			(22,442)
Purchase of treasury stock, Shares		(1,727,203)		(1,727,203)
Net income	19,918					19,918
Foreign currency translation adjustments	66				66
Ending Balance at Dec. 31, 2014	$ 129,106	$ 1	$ 162,641	$ (114,645)	$ 64	$ 81,045
Ending Balance, Shares at Dec. 31, 2014		53,000,867		18,139,958