Consolidated Statements of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Retained Earnings	Accumulated Other Comprehensive Income (Loss)
Balance at Dec. 31, 2012	$ 43,326	$ 6,103	$ 36,598	$ 625
Balance, shares at Dec. 31, 2012		30,924
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	47,954		47,954
Unrealized gain on marketable securities, net of income tax expense of $1	0
Foreign currency translation adjustment, including income tax expense (benefit)	(381)			(381)
Foreign currency translation tax expense	20
Stock-based compensation expense	454	$ 454
Common stock issued under equity compensation plan, shares		238
Common stock issued under equity compensation plan	357	$ 357
Tax benefit related to stock-based awards	(145)	$ (145)
Balance, shares at Dec. 31, 2013		31,162
Balance at Dec. 31, 2013	91,565	$ 6,769	84,552	244
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	18,795		18,795
Unrealized gain on marketable securities, net of income tax expense of $1	(18)			(18)
Foreign currency translation adjustment, including income tax expense (benefit)	(534)			(534)
Foreign currency translation tax expense	15
Stock-based compensation expense	1,066	$ 1,066
Common stock issued under equity compensation plan, shares		171
Common stock issued under equity compensation plan	378	$ 378
Tax benefit related to stock-based awards	(180)	$ (180)
Balance, shares at Dec. 31, 2014		31,333
Balance at Dec. 31, 2014	111,072	$ 8,033	103,347	(308)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	26,602		26,602
Unrealized gain on marketable securities, net of income tax expense of $1	2			2
Foreign currency translation adjustment, including income tax expense (benefit)	(1,021)			(1,021)
Foreign currency translation tax expense	17
Stock-based compensation expense	1,484	$ 1,484
Common stock issued under equity compensation plan, shares		377
Common stock issued under equity compensation plan	275	$ 275
Common stock issued under employee stock purchase plan, shares		7
Common stock issued under employee stock purchase plan	116	$ 116
Tax benefit related to stock-based awards	28	$ 28
Repurchased shares, in shares		(712)
Repurchased shares	(11,567)	$ (9,140)	(2,427)
Balance, shares at Dec. 31, 2015		31,005
Balance at Dec. 31, 2015	$ 126,991	$ 796	$ 127,522	$ (1,327)