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 income (loss)					(13,224)				(13,224)
Other comprehensive income (loss)						8,669			8,669
Stock issued for the Ascyrus Acquisition	$ 10		19,990						20,000
Stock issued for the Ascyrus Acquisition, shares	992
Equity compensation	$ 3		7,885						7,888
Equity compensation, shares	273
Exercise of options	$ 1		517						518
Exercise of options, shares	47
Employee stock purchase plan			1,561						1,561
Employee stock purchase plan, shares	84
Equity component of the convertible note issuance			16,426						16,426
Redemption and repurchase of stock to cover tax withholdings	$ (1)		(1,767)						(1,768)
Redemption and repurchase of stock to cover tax withholdings, shares	(73)
Balance at Sep. 30, 2020	$ 403		316,394		23,480	80	$ (14,591)		325,766
Balance, shares at Sep. 30, 2020	40,341						(1,484)
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)
Net income (loss)					(2,870)				(2,870)
Other comprehensive income (loss)						8,698			8,698
Stock issued for the Ascyrus Acquisition	$ 10		19,990						20,000
Stock issued for the Ascyrus Acquisition, shares	992
Equity compensation			2,518						2,518
Equity compensation, shares	6
Exercise of options			31						31
Exercise of options, shares	3
Employee stock purchase plan			873						873
Employee stock purchase plan, shares	54
Redemption and repurchase of stock to cover tax withholdings			(40)						(40)
Redemption and repurchase of stock to cover tax withholdings, shares	(2)
Balance at Sep. 30, 2020	$ 403		316,394		23,480	80	$ (14,591)		325,766
Balance, shares at Sep. 30, 2020	40,341						(1,484)
Balance (Accounting Standards Update 2020-06 [Member]) at Dec. 31, 2020		$ (16,426)		$ (3,213)				$ (19,639)
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 income (loss)					5,266				5,266
Other comprehensive income (loss)						(12,327)			(12,327)
Equity compensation	$ 3		7,892						7,895
Equity compensation, shares	252
Exercise of options	$ 1		1,921						1,922
Exercise of options, shares	158
Employee stock purchase plan	$ 1		1,608						1,609
Employee stock purchase plan, shares	87
Redemption and repurchase of stock to cover tax withholdings	$ (1)		(1,897)						(1,898)
Redemption and repurchase of stock to cover tax withholdings, shares	(75)
Balance at Sep. 30, 2021	$ 408		309,290		22,075	(5,584)	$ (14,648)		311,541
Balance, shares at Sep. 30, 2021	40,816						(1,487)
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)
Net income (loss)					10,582				10,582
Other comprehensive income (loss)						(5,010)			(5,010)
Equity compensation	$ 1		2,990						2,991
Equity compensation, shares	8
Exercise of options			191						191
Exercise of options, shares	18
Employee stock purchase plan			1,019						1,019
Employee stock purchase plan, shares	50
Redemption and repurchase of stock to cover tax withholdings			(67)						(67)
Redemption and repurchase of stock to cover tax withholdings, shares	(2)
Balance at Sep. 30, 2021	$ 408		$ 309,290		$ 22,075	$ (5,584)	$ (14,648)		$ 311,541
Balance, shares at Sep. 30, 2021	40,816						(1,487)