Consolidated Statements of Changes in Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock [Member]	Class C Special Stock [Member]	Treasury Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Deficit [Member]
Balance at Dec. 31, 2014	$ 139,785	$ 1	$ 0	$ 0	$ 159,509	$ (19,725)
Balance (in shares) at Dec. 31, 2014		11,388		0
Stock-based Compensation Expense	3,856	$ 0	0	$ 0	3,856	0
Treasury stock purchases for restricted stock vestings and forfeitures	(113)	$ 0	0	$ (113)	0	0
Treasury stock purchases for restricted stock vestings and forfeitures (in shares)		0		7
Issuance of Common Stock upon Warrant Exercise					706
Issuance of Common Shares upon Stock Option Exercise	819	$ 0	0	$ 113		0
Issuance of Common Shares upon Stock Option Exercise (in Shares)		84		(5)
Issuance of Restricted Stock Awards	0	$ 0	0	$ 0	0	0
Issuance of Restricted Stock Awards (in shares)		26		(2)
Excess Tax Benefit from Stock-based Compensation Awards	360	$ 0	0	$ 0	360	0
Net (Loss) Income	15,375	0	0	0	0	15,375
Balance at Dec. 31, 2015	160,082	$ 1	0	$ 0	164,431	(4,350)
Balance (in shares) at Dec. 31, 2015		11,498		0
Stock-based Compensation Expense	6,067	$ 0	0	$ 0	6,067	0
Treasury stock purchases for restricted stock vestings and forfeitures	(122)	$ 0	0	$ (122)	0	0
Treasury stock purchases for restricted stock vestings and forfeitures (in shares)		0		10
Issuance of Common Shares upon Stock Option and ESPP Exercise	1,570	$ 0	0	$ 122	1,448	0
Issuance of Common Shares upon Stock Option and ESPP Exercise (in shares)		119		(10)
Repurchase of Common Stock under Stock Repurchase Program	(2,500)	$ 0	0	$ 0	0	(2,500)
Repurchase of Common Stock under Stock Repurchase Program (in shares)		(65)		0
Issuance of Restricted Stock Awards	0	$ 0	0	$ 0	0	0
Issuance of Restricted Stock Awards (in shares)		37		0
Excess Tax Benefit from Stock-based Compensation Awards	617	$ 0	0	$ 0	617	0
Net (Loss) Income	3,934	0	0	0	0	3,934
Balance (Scenario, Previously Reported [Member]) at Dec. 31, 2016	169,648	1	0	0	172,563	(2,916)
Balance at Dec. 31, 2016	169,648	$ 1	0	$ 0	172,577	(2,930)
Balance (in shares) (Scenario, Previously Reported [Member]) at Dec. 31, 2016		11,589		0
Balance (in shares) at Dec. 31, 2016		11,589		0
Stock Option Forfeiture Cumulative-effect Adjustment	0	$ 0	0	$ 0	14	(14)
Stock-based Compensation Expense	6,090	0	0	0	6,090	0
Treasury stock purchases for restricted stock vestings and forfeitures	(259)	$ 0	0	$ (259)	0	0
Treasury stock purchases for restricted stock vestings and forfeitures (in shares)		0		5
Issuance of Common Shares upon Stock Option and ESPP Exercise	353	$ 0	0	$ 0	353	0
Issuance of Common Shares upon Stock Option and ESPP Exercise (in shares)		17		0
Issuance of Restricted Stock Awards	0	$ 0	0	$ 0	0	0
Issuance of Restricted Stock Awards (in shares)		50		0
Net (Loss) Income	(1,076)	$ 0	0	$ 0	0	(1,076)
Balance at Dec. 31, 2017	$ 174,756	$ 1	$ 0	$ (259)	$ 179,020	$ (4,006)
Balance (in shares) at Dec. 31, 2017		11,656		5