CONSOLIDATED STATEMENT OF EQUITY - USD ($) $ in Thousands	Total	Total Equity	Common Stock	Additional Paid-in- Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Beginning Balance (shares) at Dec. 31, 2014			26,631,000
Beginning Balance at Dec. 31, 2014		$ 157,926	$ 267	$ 171,951	$ 35	$ (14,327)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock pursuant to the employee stock purchase plan (shares)			44,000
Issuance of common stock pursuant to the employee stock purchase plan		494		494
Issuance of restricted common stock, net of cancellations (shares)			268,000
Issuance of restricted common stock, net of cancellations		3	$ 3
Realization of foreign currency translation adjustments		(35)			(35)
Surrender of restricted common stock for income tax purposes (shares)			(193,000)
Surrender of restricted common stock for income tax purposes		(3,055)	$ (1)	(3,054)
Repurchase of common stock and extinguishment (shares)			(514,000)
Repurchase of common stock and extinguishment		(8,807)	$ (5)	(3,304)		(5,498)
Stock-based compensation		6,529		6,529
Excess tax benefits from stock-based awards		(948)		(948)
Net income	$ 5,464	5,464				5,464
Ending Balance (shares) at Dec. 31, 2015			26,236,000
Ending Balance at Dec. 31, 2015		159,467	$ 264	173,564	0	(14,361)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock pursuant to the employee stock purchase plan (shares)			54,000
Issuance of common stock pursuant to the employee stock purchase plan		685	$ 1	684
Issuance of restricted common stock, net of cancellations (shares)			402,000
Issuance of restricted common stock, net of cancellations		4	$ 4
Surrender of restricted common stock for income tax purposes (shares)			(175,000)
Surrender of restricted common stock for income tax purposes		(2,904)	$ (3)	(2,901)
Issuance of common stock in connection with the exercise of vested stock options (shares)	18,000		18,000
Issuance of common stock in connection with the exercise of vested stock options		242		241
Repurchase of common stock and extinguishment (shares)	(230,163)		(230,000)
Repurchase of common stock and extinguishment	$ (4,000)	(3,961)	$ (2)	(1,527)		(2,432)
Stock-based compensation		8,359		8,359
Excess tax benefits from stock-based awards		(539)		(539)
Net income	$ 12,120	12,120				12,120
Ending Balance (shares) at Dec. 31, 2016	26,304,925		26,305,000
Ending Balance at Dec. 31, 2016		174,550	$ 264	178,959	0	(4,673)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
ASU 2016-09 adoption adjustment		440		1,139		(699)
Issuance of common stock pursuant to the employee stock purchase plan (shares)			50,000
Issuance of common stock pursuant to the employee stock purchase plan		795		795
Issuance of restricted common stock, net of cancellations (shares)			260,000
Issuance of restricted common stock, net of cancellations		0	$ 3	(3)
Surrender of restricted common stock for income tax purposes (shares)			(210,000)
Surrender of restricted common stock for income tax purposes		(3,777)	$ (2)	(3,775)
Issuance of common stock in connection with the exercise of vested stock options (shares)	67,000		67,000
Issuance of common stock in connection with the exercise of vested stock options		1,026		1,026
Repurchase of common stock and extinguishment (shares)	(775,370)		(775,000)
Repurchase of common stock and extinguishment	$ (13,300)	(13,322)	$ (7)	(5,289)		(8,026)
Stock-based compensation		7,843		7,843
Net income	$ 5,534	5,534				5,534
Ending Balance (shares) at Dec. 31, 2017	25,696,796		25,697,000
Ending Balance at Dec. 31, 2017		$ 173,089	$ 258	$ 180,695	$ 0	$ (7,864)