Condensed Consolidated Statements Of Shareholders' Equity - USD ($) shares in Thousands, $ in Thousands	Common Stock [Member]	Additional Paid-In Capital [Member] Cumulative Effect, Period of Adoption, Adjustment [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member] Cumulative Effect, Period of Adoption, Adjustment [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Treasury Stock [Member]	Cumulative Effect, Period of Adoption, Adjustment [Member]	Total
Balance at Dec. 31, 2019	$ 390		$ 271,782		$ 36,704	$ (8,589)	$ (14,591)		$ 285,696
Balance, shares at Dec. 31, 2019	39,018						(1,484)
Net loss					(10,354)				(10,354)
Other comprehensive loss:
Foreign currency translation adjustment						(29)			(29)
Comprehensive income									(10,383)
Equity component of the convertible note issuance			16,426						16,426
Equity compensation	$ 3		5,367						5,370
Equity compensation, shares	267
Exercise of options	$ 1		486						487
Exercise of options, shares	44
Employee stock purchase plan			688						688
Employee stock purchase plan, shares	30
Redemption and repurchase of stock to cover tax withholdings	$ (1)		(1,727)						(1,728)
Redemption and repurchase of stock to cover tax withholdings, shares	(71)
Balance at Jun. 30, 2020	$ 393		293,022		26,350	(8,618)	$ (14,591)		296,556
Balance, shares at Jun. 30, 2020	39,288						(1,484)
Balance at Mar. 31, 2020	$ 392		273,821		30,039	(13,052)	$ (14,591)		276,609
Balance, shares at Mar. 31, 2020	39,219						(1,484)
Net loss					(3,689)				(3,689)
Other comprehensive loss:
Foreign currency translation adjustment						4,434			4,434
Comprehensive income									745
Equity component of the convertible note issuance			16,426						16,426
Equity compensation	$ 1		2,680						2,681
Equity compensation, shares	59
Exercise of options	$ 1		110						111
Exercise of options, shares	11
Redemption and repurchase of stock to cover tax withholdings	$ (1)		(15)						(16)
Redemption and repurchase of stock to cover tax withholdings, shares	(1)
Balance at Jun. 30, 2020	$ 393		293,022		26,350	(8,618)	$ (14,591)		296,556
Balance, shares at Jun. 30, 2020	39,288						(1,484)
Balance (Accounting Standards Update 2020-06 [Member]) at Dec. 31, 2020		$ 16,400		$ 3,200
Balance at Dec. 31, 2020	$ 404		316,192		20,022	6,743	$ (14,648)		328,713
Balance, shares at Dec. 31, 2020	40,394						(1,487)
Net loss					(5,316)				(5,316)
Other comprehensive loss:
Foreign currency translation adjustment						(7,317)			(7,317)
Comprehensive income									(12,633)
Equity compensation	$ 2		4,902						4,904
Equity compensation, shares	244
Exercise of options	$ 1		1,730						1,731
Exercise of options, shares	140
Employee stock purchase plan	$ 1		589						590
Employee stock purchase plan, shares	37
Redemption and repurchase of stock to cover tax withholdings	$ (1)		(1,830)						(1,831)
Redemption and repurchase of stock to cover tax withholdings, shares	(73)
Balance (Accounting Standards Update 2020-06 [Member]) at Jun. 30, 2021		(16,426)		(3,213)				$ (19,639)
Balance at Jun. 30, 2021	$ 407		305,157		11,493	(574)	$ (14,648)		301,835
Balance, shares at Jun. 30, 2021	40,742						(1,487)
Balance at Mar. 31, 2021	$ 406		301,449		13,671	(3,547)	$ (14,648)		297,331
Balance, shares at Mar. 31, 2021	40,585						(1,487)
Net loss					(2,178)				(2,178)
Other comprehensive loss:
Foreign currency translation adjustment						2,973			2,973
Comprehensive income									795
Equity compensation			2,267						2,267
Equity compensation, shares	37
Exercise of options	$ 1		1,459						1,460
Exercise of options, shares	121
Redemption and repurchase of stock to cover tax withholdings			(18)						(18)
Redemption and repurchase of stock to cover tax withholdings, shares	(1)
Balance (Accounting Standards Update 2020-06 [Member]) at Jun. 30, 2021		$ (16,426)		$ (3,213)				$ (19,639)
Balance at Jun. 30, 2021	$ 407		$ 305,157		$ 11,493	$ (574)	$ (14,648)		$ 301,835
Balance, shares at Jun. 30, 2021	40,742						(1,487)