Statements of Changes in Stockholders' Equity - 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, 2015	21,573,000
Balance at Dec. 31, 2015	$ 22		$ 361,023	$ (125,697)	$ (1,267)	$ (90,763)	$ 143,318
Issuance of treasury stock upon purchase of common stock under employee stock purchase plan (in shares)	233,000
Issuance of treasury stock upon purchase of common stock under employee stock purchase plan		[1]		2,270		(492)	1,778
Issuance of treasury stock upon exercise of stock options, stock appreciation rights and restricted stock units by employees and directors (in shares)	1,176,000
Issuance of treasury stock upon exercise of stock options, stock appreciation rights and restricted stock units by employees and directors	$ 1	[1]	10	11,461		(9,670)	$ 1,802
Purchase of treasury stock (in shares)	(1,051,000)						(1,051,000)
Purchase of treasury stock	$ (1)	[1]		(10,666)			$ (10,666)
Equity-based compensation expenses			5,088				5,088
Net income						4,813	4,813
Change in accumulated other comprehensive income					(585)		(585)
Balance (in shares) at Dec. 31, 2016	21,931,000
Balance at Dec. 31, 2016	$ 22		366,121	(122,632)	(1,852)	(96,112)	145,547
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		[1]		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)	663,000
Issuance of treasury stock upon exercise of stock options, stock appreciation rights and restricted stock units by employees and directors		[1]	59	6,500		(5,397)	$ 1,162
Purchase of treasury stock (in shares)	(389,000)						(389,000)
Purchase of treasury stock		[1]		(4,490)			$ (4,490)
Equity-based compensation expenses			5,861				5,861
Net income						(3,003)	(3,003)
Change in accumulated other comprehensive income					(22)		(22)
Balance (in shares) at Dec. 31, 2017	22,433,000
Balance at Dec. 31, 2017	$ 22		372,041	(118,397)	(1,874)	(104,842)	146,950
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		[1]		2,275		(271)	2,004
Issuance of treasury stock upon exercise of stock options, stock appreciation rights and restricted stock units by employees and directors (in shares)	618,000
Issuance of treasury stock upon exercise of stock options, stock appreciation rights and restricted stock units by employees and directors	$ 1		10	6,114		(5,387)	$ 738
Purchase of treasury stock (in shares)	(1,015,000)						(1,015,000)
Purchase of treasury stock	$ (1)			(12,317)			$ (12,318)
Equity-based compensation expenses			6,804				6,804
Net income						(1,957)	(1,957)
Change in accumulated other comprehensive income					(450)		(450)
Adoption of accounting standard at Dec. 31, 2017						94	94
Balance (in shares) at Dec. 31, 2018	22,266,000
Balance at Dec. 31, 2018	$ 22		$ 378,855	$ (122,325)	$ (2,324)	$ (112,363)	$ 141,865

[1] Represents an amount lower than $1.