Condensed Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands		Common Stock [Member]		Additional Paid-in Capital [Member]	Treasury Stock [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Total
Balance (in shares) at Dec. 31, 2016		21,932,000
Balance at Dec. 31, 2016		$ 22		$ 366,121	$ (122,632)	$ (96,112)	$ (1,852)	$ 145,547
Net income						(2,874)		(2,874)
Change in accumulated other comprehensive income							394	394
Purchase of treasury stock (in shares)		(379,000)
Purchase of treasury stock					(4,365)			(4,365)
Issuance of treasury stock upon purchase of common stock under employee stock purchase plan (in shares)		227,000
Issuance of treasury stock upon purchase of common stock under employee stock purchase plan					2,225	(330)		1,895
Issuance of treasury stock upon exercise of stock options, stock appreciation rights and restricted stock units by employees and directors (in shares)		496,000
Issuance of treasury stock upon exercise of stock options, stock appreciation rights and restricted stock units by employees and directors					4,863	(4,235)		628
Equity-based compensation				4,526				4,526
Balance (in shares) at Sep. 30, 2017		22,276,000
Balance at Sep. 30, 2017		$ 22		370,647	(119,909)	(103,551)	(1,458)	145,751
Balance (in shares) at Jun. 30, 2017		22,151,000
Balance at Jun. 30, 2017		$ 22		369,209	(120,855)	(102,867)	(1,391)	144,118
Net income						578		578
Change in accumulated other comprehensive income							(67)	(67)
Purchase of treasury stock (in shares)		(131,000)
Purchase of treasury stock			[1]		(1,563)			(1,563)
Issuance of treasury stock upon purchase of common stock under employee stock purchase plan (in shares)		114,000
Issuance of treasury stock upon purchase of common stock under employee stock purchase plan			[1]		1,117	(163)		954
Issuance of treasury stock upon exercise of stock options, stock appreciation rights and restricted stock units by employees and directors (in shares)		142,000
Issuance of treasury stock upon exercise of stock options, stock appreciation rights and restricted stock units by employees and directors			[1]		1,392	(1,099)		293
Equity-based compensation				1,438				1,438
Balance (in shares) at Sep. 30, 2017		22,276,000
Balance at Sep. 30, 2017		$ 22		370,647	(119,909)	(103,551)	(1,458)	145,751
Balance (in shares) at Dec. 31, 2017		22,433,000
Balance at Dec. 31, 2017		$ 22		372,041	(118,397)	(104,842)	(1,874)	146,950
Net income						(1,637)		(1,637)
Change in accumulated other comprehensive income							(784)	$ (784)
Purchase of treasury stock (in shares)		(804,000)						(803,762)
Purchase of treasury stock		$ (1)			(9,827)			$ (9,827)
Issuance of treasury stock upon purchase of common stock under employee stock purchase plan (in shares)		230,000
Issuance of treasury stock upon purchase of common stock under employee stock purchase plan					2,275	(269)		2,006
Issuance of treasury stock upon exercise of stock options, stock appreciation rights and restricted stock units by employees and directors (in shares)		473,000
Issuance of treasury stock upon exercise of stock options, stock appreciation rights and restricted stock units by employees and directors		$ 1		10	4,663	(4,219)		455
Equity-based compensation				5,111				5,111
Balance (in shares) at Sep. 30, 2018		22,332,000
Balance at Sep. 30, 2018		$ 22		377,162	(121,286)	(110,873)	(2,658)	142,367
Balance (in shares) at Jun. 30, 2018		22,461,000
Balance at Jun. 30, 2018		$ 22		375,410	(119,200)	(110,420)	(2,698)	143,114
Net income						405		405
Change in accumulated other comprehensive income							40	40
Purchase of treasury stock (in shares)		(317,000)
Purchase of treasury stock			[1]		(3,958)			(3,958)
Issuance of treasury stock upon purchase of common stock under employee stock purchase plan (in shares)		112,000
Issuance of treasury stock upon purchase of common stock under employee stock purchase plan			[1]		1,106	(105)		1,001
Issuance of treasury stock upon exercise of stock options, stock appreciation rights and restricted stock units by employees and directors (in shares)		76,000
Issuance of treasury stock upon exercise of stock options, stock appreciation rights and restricted stock units by employees and directors			[1]		766	(753)		13
Equity-based compensation				1,752				1,752
Balance (in shares) at Sep. 30, 2018		22,332,000
Balance at Sep. 30, 2018		$ 22		$ 377,162	$ (121,286)	(110,873)	$ (2,658)	142,367
Cumulative effect adjustment on retained earnings **)	[2]					$ 94		$ 94

[1] Represents an amount lower than $1.

[2] Resulting from adoption of ASC 606.