Restructuring Costs - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Mar. 31, 2019	Dec. 31, 2018
Restructuring Cost and Reserve [Line Items]
Fixed asset impairment	$ 0	$ 0
2019 French Restructuring Obligation
Restructuring Cost and Reserve [Line Items]
Restructuring costs	172,000	4,855,000
Operating lease, impairment loss		629,000
Fixed asset impairment		887,000
Restructuring reserve	248,000	1,922,000		$ 0
2019 French Restructuring Obligation | Employee Severance
Restructuring Cost and Reserve [Line Items]
Charges for employee severance, benefits and other costs	172,000	4,339,000
2019 French Restructuring Obligation | Retirement Indemnity Obligation
Restructuring Cost and Reserve [Line Items]
Restructuring costs		1,000,000
Corporate Workforce Reduction
Restructuring Cost and Reserve [Line Items]
Restructuring income	215,000
Benefit related to share based compensation forfeitures	421,000
Corporate Workforce Reduction | Employee Severance
Restructuring Cost and Reserve [Line Items]
Percent reduction in workforce			50.00%
2019 Corporate Restructuring Obligations
Restructuring Cost and Reserve [Line Items]
Restructuring costs		1,755,000
Fixed asset impairment		288,000
Restructuring reserve	272,000	1,080,000		$ 0
Write-off of property, plant and equipment		125,000
Share-based compensation forfeitures related to the employees affected by the global reduction in workforce		2,064,000
2019 Corporate Restructuring Obligations | Employee Severance
Restructuring Cost and Reserve [Line Items]
Restructuring costs		3,406,000
Charges for employee severance, benefits and other costs	206,000	$ 3,406,000
Accrued Liabilities | 2019 French Restructuring Obligation
Restructuring Cost and Reserve [Line Items]
Restructuring reserve	$ 248,000