Condensed Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) shares in Thousands, $ in Thousands	Common Stock Outstanding [Member]	Additional Paid-in Capital [Member]	Treasury Stock [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Total
Balances (in shares) at Dec. 31, 2017	32,112		7,688
Balances at Dec. 31, 2017	$ 5	$ 297,950	$ (71,793)	$ (27,089)	$ (705)	$ 198,368
Issuance of common stock in connection with employee stock purchase plan (in shares)	108
Issuance of common stock in connection with employee stock purchase plan		1,007				1,007
Issuance of common stock in connection with exercise of options (in shares)	8
Issuance of common stock in connection with exercise of options		39				39
Vesting of restricted stock units (in shares)	74
Vesting of restricted stock units
Purchases of treasury stock in connection with tax withholdings on restricted stock grants (in shares)			36
Purchases of treasury stock in connection with tax withholdings on restricted stock grants			$ (557)			(557)
Repurchases of common stock (in shares)	(338)		338
Repurchases of common stock			$ (4,123)			(4,123)
Stock-based compensation		2,871				2,871
Comprehensive income (loss)				(424)	525	101
Cumulative-effect adjustment from adoption of ASU 2014-09 at Dec. 31, 2017				4,353		4,353
Balances (in shares) at Mar. 31, 2018	31,964		8,062
Balances at Mar. 31, 2018	$ 5	301,867	$ (76,473)	(23,160)	(180)	202,059
Balances (in shares) at Dec. 31, 2017	32,112		7,688
Balances at Dec. 31, 2017	$ 5	297,950	$ (71,793)	(27,089)	(705)	198,368
Comprehensive income (loss)						(5,016)
Cumulative-effect adjustment from adoption of ASU 2014-09 at Dec. 31, 2017				4,353		4,353
Balances (in shares) at Sep. 30, 2018	32,257		8,252
Balances at Sep. 30, 2018	$ 5	308,098	$ (78,751)	(27,338)	(1,119)	200,895
Balances (in shares) at Mar. 31, 2018	31,964		8,062
Balances at Mar. 31, 2018	$ 5	301,867	$ (76,473)	(23,160)	(180)	202,059
Issuance of common stock in connection with exercise of options (in shares)	51
Issuance of common stock in connection with exercise of options		377				377
Vesting of restricted stock units (in shares)	159
Vesting of restricted stock units
Purchases of treasury stock in connection with tax withholdings on restricted stock grants (in shares)			63
Purchases of treasury stock in connection with tax withholdings on restricted stock grants			$ (819)			(819)
Repurchases of common stock (in shares)	(99)		99
Repurchases of common stock			$ (1,125)			(1,125)
Stock-based compensation		2,699				2,699
Comprehensive income (loss)				(2,096)	(771)	(2,867)
Balances (in shares) at Jun. 30, 2018	32,075		8,224
Balances at Jun. 30, 2018	$ 5	304,943	$ (78,417)	(25,256)	(951)	200,324
Issuance of common stock in connection with employee stock purchase plan (in shares)	92
Issuance of common stock in connection with employee stock purchase plan		824				824
Issuance of common stock in connection with exercise of options (in shares)	9
Issuance of common stock in connection with exercise of options		53				53
Vesting of restricted stock units (in shares)	81
Vesting of restricted stock units
Purchases of treasury stock in connection with tax withholdings on restricted stock grants (in shares)			28
Purchases of treasury stock in connection with tax withholdings on restricted stock grants			$ (334)			(334)
Stock-based compensation		2,278				2,278
Comprehensive income (loss)				(2,082)	(168)	(2,250)
Balances (in shares) at Sep. 30, 2018	32,257		8,252
Balances at Sep. 30, 2018	$ 5	308,098	$ (78,751)	(27,338)	(1,119)	200,895
Balances (in shares) at Dec. 31, 2018	32,382		8,295
Balances at Dec. 31, 2018	$ 5	310,660	$ (79,142)	(30,452)	(1,276)	199,795
Issuance of common stock in connection with employee stock purchase plan (in shares)	87
Issuance of common stock in connection with employee stock purchase plan		782				782
Issuance of common stock in connection with exercise of options (in shares)	87
Issuance of common stock in connection with exercise of options		518				518
Vesting of restricted stock units (in shares)	104
Vesting of restricted stock units
Purchases of treasury stock in connection with tax withholdings on restricted stock grants (in shares)			54
Purchases of treasury stock in connection with tax withholdings on restricted stock grants			$ (557)			(557)
Repurchases of common stock (in shares)	(314)		314
Repurchases of common stock			$ (3,917)			(3,917)
Stock-based compensation		3,469				3,469
Comprehensive income (loss)				(2,691)	(52)	(2,743)
Balances (in shares) at Mar. 31, 2019	32,346		8,663
Balances at Mar. 31, 2019	$ 5	315,429	$ (83,616)	(33,143)	(1,328)	197,347
Balances (in shares) at Dec. 31, 2018	32,382		8,295
Balances at Dec. 31, 2018	$ 5	310,660	$ (79,142)	(30,452)	(1,276)	$ 199,795
Issuance of common stock in connection with exercise of options (in shares)						217
Comprehensive income (loss)						$ (4,565)
Balances (in shares) at Sep. 30, 2019	32,350		9,246
Balances at Sep. 30, 2019	$ 5	322,183	$ (90,908)	(34,540)	(1,753)	194,987
Balances (in shares) at Mar. 31, 2019	32,346		8,663
Balances at Mar. 31, 2019	$ 5	315,429	$ (83,616)	(33,143)	(1,328)	197,347
Issuance of common stock in connection with exercise of options (in shares)	69
Issuance of common stock in connection with exercise of options		326				326
Vesting of restricted stock units (in shares)	176
Vesting of restricted stock units
Purchases of treasury stock in connection with tax withholdings on restricted stock grants (in shares)			72
Purchases of treasury stock in connection with tax withholdings on restricted stock grants			$ (918)			(918)
Repurchases of common stock (in shares)	(300)		300
Repurchases of common stock			$ (3,790)			(3,790)
Stock-based compensation		2,601				2,601
Comprehensive income (loss)				(710)	36	(674)
Balances (in shares) at Jun. 30, 2019	32,291		9,035
Balances at Jun. 30, 2019	$ 5	318,356	$ (88,324)	(33,853)	(1,292)	194,892
Issuance of common stock in connection with employee stock purchase plan (in shares)	85
Issuance of common stock in connection with employee stock purchase plan		751				751
Issuance of common stock in connection with exercise of options (in shares)	53
Issuance of common stock in connection with exercise of options		267				267
Vesting of restricted stock units (in shares)	92
Vesting of restricted stock units
Repurchases of common stock (in shares)	(171)		171
Repurchases of common stock			$ (2,060)			(2,060)
Stock-based compensation		2,809				2,809
Comprehensive income (loss)				(687)	(461)	(1,148)
Purchases of treasury stock in connection with tax withholdings on restricted stock grants and exercise of options (in shares)			40
Purchases of treasury stock in connection with tax withholdings on restricted stock grants and exercise of options			$ (524)			(524)
Balances (in shares) at Sep. 30, 2019	32,350		9,246
Balances at Sep. 30, 2019	$ 5	$ 322,183	$ (90,908)	$ (34,540)	$ (1,753)	$ 194,987