Summary of Significant Accounting Policies - Schedule of Restricted Cash (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Restricted Cash and Cash Equivalents Items [Line Items]
Other assets	$ 1,321	$ 1,730	$ 1,902	$ 364
Restricted Cash		1,994
Restricted cash, current (included within prepaid expenses and other current assets)	0	264	$ 0	$ 0
Other Assets
Restricted Cash and Cash Equivalents Items [Line Items]
Other assets	1,321	1,730
Letter of credit security: Cambridge lease | Letter of Credit
Restricted Cash and Cash Equivalents Items [Line Items]
Other assets	0	264
Letter of credit security: Waltham lease | Letter of Credit
Restricted Cash and Cash Equivalents Items [Line Items]
Other assets	250	250
Letter of credit security: Vienna Austria lease | Letter of Credit
Restricted Cash and Cash Equivalents Items [Line Items]
Other assets	216	336
Letter of credit security: Boston lease | Letter of Credit
Restricted Cash and Cash Equivalents Items [Line Items]
Other assets	$ 855	$ 1,144