Condensed Consolidated Statements of Redeemable Convertible Preferred Stock and Stockholders’ Deficit - USD ($) $ in Thousands	Total	Common Stock	Treasury Stock	Additional Paid-In Capital	Accumulated Deficit	Accumulated Other Comprehensive Loss	Series 1 Preferred
Preferred stock, beginning balance (in shares) at Dec. 31, 2019							538,000
Preferred stock, beginning balance at Dec. 31, 2019							$ 21,468
Increase (Decrease) in Temporary Equity [Roll Forward]
Conversion of redeemable preferred stock into common stock (in shares)		40,000					(4,000)
Conversion of redeemable convertible preferred stock into common stock	$ 160	$ 1		$ 159			$ (160)
Preferred stock, ending balance (in shares) at Mar. 31, 2020							534,000
Preferred stock, ending balance at Mar. 31, 2020							$ 21,308
Balance, beginning of period (in shares) at Dec. 31, 2019		5,076,593	67,746
Balance, beginning of period at Dec. 31, 2019	(26,217)	$ 507	$ (5,056)	511,684	$ (533,025)	$ (327)
Increase (Decrease) in Stockholders' Equity
1-for-10 Reverse Stock Split	0	$ (457)		457
Share-based compensation	1,323			1,323
Issuance of common stock upon vesting of restricted stock units (in shares)		1,045
Conversion of redeemable preferred stock into common stock (in shares)		40,000					(4,000)
Conversion of redeemable convertible preferred stock into common stock	160	$ 1		159			$ (160)
Comprehensive income (loss)	17,563				17,576	(13)
Balance, end of period (in shares) at Mar. 31, 2020		5,117,638	67,746
Balance, end of period at Mar. 31, 2020	(7,171)	$ 51	$ (5,056)	513,623	(515,449)	(340)
Preferred stock, beginning balance (in shares) at Dec. 31, 2019							538,000
Preferred stock, beginning balance at Dec. 31, 2019							$ 21,468
Preferred stock, ending balance (in shares) at Sep. 30, 2020							534,000
Preferred stock, ending balance at Sep. 30, 2020							$ 21,308
Balance, beginning of period (in shares) at Dec. 31, 2019		5,076,593	67,746
Balance, beginning of period at Dec. 31, 2019	(26,217)	$ 507	$ (5,056)	511,684	(533,025)	(327)
Increase (Decrease) in Stockholders' Equity
Comprehensive income (loss)	(26,531)
Balance, end of period (in shares) at Sep. 30, 2020		5,127,525	67,746
Balance, end of period at Sep. 30, 2020	(48,030)	$ 51	$ (5,056)	516,858	(559,530)	(353)
Preferred stock, beginning balance (in shares) at Mar. 31, 2020							534,000
Preferred stock, beginning balance at Mar. 31, 2020							$ 21,308
Preferred stock, ending balance (in shares) at Jun. 30, 2020							534,000
Preferred stock, ending balance at Jun. 30, 2020							$ 21,308
Balance, beginning of period (in shares) at Mar. 31, 2020		5,117,638	67,746
Balance, beginning of period at Mar. 31, 2020	(7,171)	$ 51	$ (5,056)	513,623	(515,449)	(340)
Increase (Decrease) in Stockholders' Equity
Share-based compensation	1,564			1,564
Issuance of common stock - Employee Stock Purchase Plan (in shares)		9,526
Issuance of common stock - Employee Stock Purchase Plan	65	$ 0		65
Issuance of common stock upon vesting of restricted stock units (in shares)		361
Comprehensive income (loss)	(43,243)				(43,194)	(49)
Balance, end of period (in shares) at Jun. 30, 2020		5,127,525	67,746
Balance, end of period at Jun. 30, 2020	(48,785)	$ 51	$ (5,056)	515,252	(558,643)	(389)
Preferred stock, ending balance (in shares) at Sep. 30, 2020							534,000
Preferred stock, ending balance at Sep. 30, 2020							$ 21,308
Increase (Decrease) in Stockholders' Equity
Share-based compensation	1,606			1,606
Comprehensive income (loss)	(851)				(887)	36
Balance, end of period (in shares) at Sep. 30, 2020		5,127,525	67,746
Balance, end of period at Sep. 30, 2020	(48,030)	$ 51	$ (5,056)	516,858	(559,530)	(353)
Preferred stock, beginning balance (in shares) at Dec. 31, 2020							452,000
Preferred stock, beginning balance at Dec. 31, 2020	18,036						$ 18,036
Preferred stock, ending balance (in shares) at Mar. 31, 2021							452,000
Preferred stock, ending balance at Mar. 31, 2021							$ 18,036
Balance, beginning of period (in shares) at Dec. 31, 2020		8,385,650	67,746
Balance, beginning of period at Dec. 31, 2020	(2,497)	$ 84	$ (5,056)	543,561	(540,747)	(339)
Increase (Decrease) in Stockholders' Equity
Share-based compensation	903			903
Exercise of restricted stock unit awards (in shares)		369
Exercise of restricted stock unit awards	0
Comprehensive income (loss)	(11,267)				(11,267)
Balance, end of period (in shares) at Mar. 31, 2021		8,386,019	67,746
Balance, end of period at Mar. 31, 2021	(12,861)	$ 84	$ (5,056)	544,464	(552,014)	(339)
Preferred stock, beginning balance (in shares) at Dec. 31, 2020							452,000
Preferred stock, beginning balance at Dec. 31, 2020	18,036						$ 18,036
Preferred stock, ending balance (in shares) at Sep. 30, 2021							452,000
Preferred stock, ending balance at Sep. 30, 2021	18,036						$ 18,036
Balance, beginning of period (in shares) at Dec. 31, 2020		8,385,650	67,746
Balance, beginning of period at Dec. 31, 2020	(2,497)	$ 84	$ (5,056)	543,561	(540,747)	(339)
Increase (Decrease) in Stockholders' Equity
Comprehensive income (loss)	(12,245)
Balance, end of period (in shares) at Sep. 30, 2021		8,465,549	67,746
Balance, end of period at Sep. 30, 2021	(12,165)	$ 84	$ (5,056)	546,138	(552,983)	(348)
Preferred stock, beginning balance (in shares) at Mar. 31, 2021							452,000
Preferred stock, beginning balance at Mar. 31, 2021							$ 18,036
Preferred stock, ending balance (in shares) at Jun. 30, 2021							452,000
Preferred stock, ending balance at Jun. 30, 2021							$ 18,036
Balance, beginning of period (in shares) at Mar. 31, 2021		8,386,019	67,746
Balance, beginning of period at Mar. 31, 2021	(12,861)	$ 84	$ (5,056)	544,464	(552,014)	(339)
Increase (Decrease) in Stockholders' Equity
Share-based compensation	821			821
Exercise of restricted stock unit awards (in shares)		79,530
Exercise of restricted stock unit awards	0
Comprehensive income (loss)	(2,202)				(2,202)
Balance, end of period (in shares) at Jun. 30, 2021		8,465,549	67,746
Balance, end of period at Jun. 30, 2021	(14,242)	$ 84	$ (5,056)	545,285	(554,216)	(339)
Preferred stock, ending balance (in shares) at Sep. 30, 2021							452,000
Preferred stock, ending balance at Sep. 30, 2021	18,036						$ 18,036
Increase (Decrease) in Stockholders' Equity
Share-based compensation	853			853
Comprehensive income (loss)	1,224				1,233	(9)
Balance, end of period (in shares) at Sep. 30, 2021		8,465,549	67,746
Balance, end of period at Sep. 30, 2021	$ (12,165)	$ 84	$ (5,056)	$ 546,138	$ (552,983)	$ (348)