Summary of Significant Accounting Policies - Additional Information (Details) $ / shares in Units, € in Thousands, $ in Thousands	9 Months Ended
	Sep. 30, 2021 USD ($) Segment $ / shares	Sep. 30, 2021 EUR (€)	Jan. 28, 2021 $ / shares	Dec. 31, 2020 $ / shares	Oct. 27, 2020 $ / shares	Jun. 10, 2020 $ / shares
Accounting Policies [Line Items]
Ordinary shares, par value \| $ / shares	$ 0.01		$ 0.01	$ 0.01		$ 0.01
Number of business segments \| Segment	1
October Offering
Accounting Policies [Line Items]
Ordinary shares, par value \| $ / shares	$ 0.01				$ 0.01
June 3 SPA
Accounting Policies [Line Items]
Ordinary shares, par value \| $ / shares	0.01
June 30 SPA
Accounting Policies [Line Items]
Ordinary shares, par value \| $ / shares	$ 0.01
Certificates Of Deposit
Accounting Policies [Line Items]
Restricted cash	$ 30
Warrants Issued \| October Offering
Accounting Policies [Line Items]
Restricted cash	11
Warrants Issued \| June 3 SPA
Accounting Policies [Line Items]
Restricted cash	17
Warrants Issued \| June 30 SPA
Accounting Policies [Line Items]
Restricted cash	6
Maximum
Accounting Policies [Line Items]
Cash, FDIC insured amount	250
Cash, DGS insured amount	$ 116	€ 100