Consolidated Statements of Stockholders' Deficit - USD ($) $ in Millions	Common Stock [Member]	Additional Paid-in Capital [Member]	AOCI Attributable to Parent [Member]	Retained Earnings [Member]	Total
Balance at Dec. 31, 2018		$ 303.9	$ 55.9	$ (383.9)	$ (24.1)
Balance, shares at Dec. 31, 2018	20,870,397
Foreign currency translation adjustments			(2.4)		(2.4)
Actuarial gains on pension plan			(6.9)		(6.9)
Change in fair value of hedging instrument			2.9		2.9
Reclassification of gain (loss) on hedging instrument to comprehensive income			(4.4)		(4.4)
Conversion of awards previously classified as derivatives		0.8			0.8
Shares issued in earnout		8.6			8.6
Shares issued in earnout, shares	1,323,558
Shares issued upon net settlement of RSUs		(0.9)			(0.9)
Shares issued upon net settlement of RSUs, shares	36,813
Stock-based compensation expense		8.2			8.2
Net loss				(41.1)	(41.1)
Balance at Dec. 31, 2019		320.6	45.1	(425.0)	(59.3)
Balance, shares at Dec. 31, 2019	22,230,768
Foreign currency translation adjustments			(5.4)		(5.4)
Actuarial gains on pension plan			(7.2)		(7.2)
Change in fair value of hedging instrument			(2.9)		(2.9)
Reclassification of gain (loss) on hedging instrument to comprehensive income			1.5		1.5
Shares issued upon net settlement of RSUs		(0.7)			(0.7)
Shares issued upon net settlement of RSUs, shares	192,058
Shares issued under ESPP
Shares issued under ESPP, shares	7,649
Stock-based compensation expense		4.7			4.7
Net loss				(32.4)	(32.4)
Balance at Dec. 31, 2020		324.6	31.1	(457.4)	(101.7)
Balance, shares at Dec. 31, 2020	22,430,475
Foreign currency translation adjustments			0.4		0.4
Actuarial gains on pension plan			10.5		10.5
Change in fair value of hedging instrument			0.3		0.3
Reclassification of gain (loss) on hedging instrument to comprehensive income			1.5		1.5
Shares issued upon net settlement of RSUs		(6.4)			(6.4)
Shares issued upon net settlement of RSUs, shares	324,122
Shares issued upon exercise of warrants		42.4			42.4
Shares issued upon exercise of warrants, shares	3,678,965
Stock-based compensation expense		11.7			11.7
Net loss				(36.7)	(36.7)
Balance at Dec. 31, 2021		$ 372.3	$ 43.8	$ (494.1)	$ (78.0)
Balance, shares at Dec. 31, 2021	26,433,562