Shareholders' (Deficit) / Equity - Additional Information (Details)

v3.20.4

Shareholders' (Deficit) / Equity - Additional Information (Details) $ / shares in Units, € in Thousands, $ in Thousands										1 Months Ended	12 Months Ended
	Oct. 31, 2020 $ / shares shares	Oct. 27, 2020 USD ($) $ / shares shares	Jul. 02, 2020 $ / shares shares	Jun. 05, 2020 $ / shares shares	Jun. 03, 2020 USD ($) $ / shares shares	Feb. 16, 2018 USD ($) $ / shares shares	May 18, 2017 USD ($) $ / shares shares	Dec. 16, 2016 USD ($) $ / shares shares	Nov. 18, 2015 USD ($) $ / shares shares	Jun. 30, 2020 USD ($) $ / shares shares	Dec. 31, 2020 USD ($) Vote $ / shares shares	Dec. 31, 2018	Jun. 10, 2020 shares	Dec. 31, 2019 $ / shares shares	Oct. 31, 2019 shares	Sep. 30, 2019 USD ($) shares	Sep. 30, 2019 EUR (€) shares	Aug. 19, 2019 USD ($) shares	Aug. 19, 2019 EUR (€) shares	Jul. 15, 2019 USD ($) shares	Jul. 15, 2019 EUR (€) shares	Dec. 14, 2018 USD ($) shares	Dec. 14, 2018 EUR (€) shares	May 30, 2018 $ / shares shares	May 29, 2018 shares	May 15, 2018 $ / shares	Apr. 27, 2018 $ / shares shares	Mar. 13, 2018 $ / shares shares	Mar. 12, 2018 $ / shares	Feb. 15, 2018 shares	Dec. 09, 2016 $ / shares shares	Oct. 14, 2015 $ / shares shares
Class Of Stock [Line Items]
Ordinary shares, shares authorized						44,557,606	7,956,715		3,659,453		150,000,000		100,000,000	50,000,000										50,000,000				44,557,606				413,110
Ordinary shares, shares issued											49,431,028			14,868,973														413,110				413,110
Ordinary shares, par value | $ / shares						$ 0.01	$ 0.01		$ 0.01		$ 0.01			$ 0.01										$ 0.01				$ 0.001	$ 0.0001			$ 0.01
Share consolidation basis nominal value per share | $ / shares																										$ 0.01571
Share consolidation basis, Renominalisation value per share | $ / shares																										0.01
Increase in common stock, shares authorized																									5,442,394					36,600,891
Proceeds from registered direct offerings, net of transaction costs | $											$ 32,200
Number of vote per common share | Vote											1
Common stock rights and preferences											The holders of ordinary shares have no preemptive or other subscription rights, and there are no redemption or sinking fund provisions with respect to such shares
Undesignated preferred shares, par value | $ / shares											$ 0.01			$ 0.01
Undesignated preferred shares, authorized											100,000,000			100,000,000
Undesignated preferred shares issued											0			0
Preferred stock, conversion basis												one-for-one
Series B Convertible Preferred Shares
Class Of Stock [Line Items]
Temporary equity, shares authorized																												4,801,493
Temporary equity, par value | $ / shares																												$ 0.001	0.0001
Temporary equity, shares issued																												4,363,856
Undesignated Preferred Shares
Class Of Stock [Line Items]
Undesignated preferred shares, par value | $ / shares											$ 0.01
Undesignated preferred shares, authorized											100,000,000
Undesignated preferred shares issued											0				0
Series A Convertible Preferred Shares
Class Of Stock [Line Items]
Share consolidation basis nominal value per share | $ / shares																										0.01571
Share consolidation basis, Renominalisation value per share | $ / shares																										0.01
Temporary equity, shares authorized									3,022,915																			3,032,463			9,548
Temporary equity, par value | $ / shares									$ 0.01																			$ 0.001	$ 0.0001		$ 0.01
Temporary equity, shares issued								1,518,137	1,514,320																			3,032,457
Temporary equity shares price per share | $ / shares								$ 15.71	$ 15.71
Gross cash proceeds from Issuance of convertible preferred stock | $								$ 20,851	$ 20,701
Series A Convertible Preferred Shares | Founders
Class Of Stock [Line Items]
Conversion of debt amount | $									$ 90
Convertible preferred stock issued upon conversion									5,728
Series B-1 Convertible Preferred Shares
Class Of Stock [Line Items]
Share consolidation basis nominal value per share | $ / shares																										0.01571
Share consolidation basis, Renominalisation value per share | $ / shares																										$ 0.01
Temporary equity, shares authorized							2,654,215
Temporary equity, par value | $ / shares							$ 0.01
Temporary equity, shares issued							2,654,206
Temporary equity shares price per share | $ / shares							$ 17.28
Gross cash proceeds from Issuance of convertible preferred stock | $							$ 45,867
Series B-2 Convertible Preferred Shares
Class Of Stock [Line Items]
Temporary equity, shares authorized						2,147,278	1,042,728
Temporary equity, par value | $ / shares						$ 0.01	$ 0.01
Temporary equity, shares issued						1,709,650
Temporary equity shares price per share | $ / shares						$ 18.85
Gross cash proceeds from Issuance of convertible preferred stock | $						$ 32,230
Silicon Valley Bank and Life Sciences Fund II LLC | Series B Convertible Preferred Shares
Class Of Stock [Line Items]
Number of warrants to purchase ordinary shares											19,890																19,890
Warrants to purchase ordinary shares, exercise price | $ / shares											$ 18.85																$ 18.85
Ordinary Shares
Class Of Stock [Line Items]
Number of warrants to purchase ordinary shares											19,890																19,890
June 3 SPA
Class Of Stock [Line Items]
Ordinary shares, par value | $ / shares											$ 0.01
Pfizer License Agreement | Series A Convertible Preferred Shares
Class Of Stock [Line Items]
Temporary equity, shares issued									190,961
Temporary equity, additional shares issued								190,961
June 3 Offering | June 3 SPA
Class Of Stock [Line Items]
Ordinary shares, shares issued					2,971,770
Ordinary shares, par value | $ / shares					$ 0.01
Offering price per share | $ / shares					$ 1.6825
Aggregate gross proceeds from ordinary shares | $					$ 5,000
Proceeds from registered direct offerings, net of transaction costs | $					$ 4,300
Warrants closing date					Jun. 05, 2020
June 30 Offering | June 30 SPA
Class Of Stock [Line Items]
Ordinary shares, shares issued										3,372,686
Ordinary shares, par value | $ / shares										$ 0.01
Offering price per share | $ / shares										$ 1.4825
Aggregate gross proceeds from ordinary shares | $										$ 5,000
Proceeds from registered direct offerings, net of transaction costs | $										$ 4,200
Warrants closing date										Jul. 02, 2020
October Offering
Class Of Stock [Line Items]
Ordinary shares, shares issued		15,511,537
Ordinary shares, par value | $ / shares		$ 0.01									$ 0.01
Aggregate gross proceeds from ordinary shares | $		$ 17,400
Proceeds from registered direct offerings, net of transaction costs | $		$ 15,500									$ 900
Number of warrants to purchase ordinary shares	1,884,615										1,268,859
Warrants to purchase ordinary shares, exercise price | $ / shares	$ 0.8125	$ 0.65
Warrants expiry date	Oct. 22, 2025	Oct. 27, 2025
Percentage of ordinary shares issued to purchase warrants	7.00%
October Offering | Maximum
Class Of Stock [Line Items]
Number of warrants to purchase ordinary shares		20,192,307
October Offering | Pre-Funded Warrants
Class Of Stock [Line Items]
Offering price per share | $ / shares		$ 0.01
Proceeds from registered direct offerings, net of transaction costs | $											$ 110
Number of warrants to purchase ordinary shares		11,411,539
Warrants to purchase ordinary shares, exercise price | $ / shares		$ 0.64
October Offering | Warrant
Class Of Stock [Line Items]
Offering price per share | $ / shares		$ 0.65
Number of warrants to purchase ordinary shares		20,192,307
Warrants to purchase ordinary shares, exercise price | $ / shares		$ 0.65
Private Placement | Securities Purchase Agreement
Class Of Stock [Line Items]
Number of warrants to purchase ordinary shares				208,023
Warrants to purchase ordinary shares, exercise price | $ / shares				$ 2.1031	$ 1.62
Warrants expiry date				Jun. 03, 2025	Dec. 05, 2025
Percentage of ordinary shares issued to purchase warrants				7.00%
Private Placement | Securities Purchase Agreement | Maximum
Class Of Stock [Line Items]
Number of warrants to purchase ordinary shares					1,485,885
Private Placement | June 30 SPA
Class Of Stock [Line Items]
Number of warrants to purchase ordinary shares			236,088
Warrants to purchase ordinary shares, exercise price | $ / shares			$ 1.8531							$ 1.42
Warrants expiry date			Jun. 30, 2025							Jan. 02, 2026
Percentage of ordinary shares issued to purchase warrants			7.00%
Private Placement | June 30 SPA | Maximum
Class Of Stock [Line Items]
Number of warrants to purchase ordinary shares										1,686,343
Private Placement | June 3 SPA
Class Of Stock [Line Items]
Warrants closing date					Jun. 05, 2020
Number of warrants to purchase ordinary shares				208,023
Warrants to purchase ordinary shares, exercise price | $ / shares				$ 2.1031	$ 1.62
Warrants expiry date				Jun. 03, 2025	Dec. 05, 2025
Percentage of ordinary shares issued to purchase warrants				7.00%
Private Placement | June 3 SPA | Maximum
Class Of Stock [Line Items]
Number of warrants to purchase ordinary shares					1,485,885
Supplier
Class Of Stock [Line Items]
Common stock, maximum shares authorized for subscription																						700,000	700,000
Maximum subscription units to be accepted																199,056	199,056	245,493	245,493	17,222	17,222	190,615	190,615
Issuance of ordinary shares under subscription agreement | $																$ 1,260		$ 1,670		$ 110		$ 1,360
Payment receivable upon common stock subscription agreement																$ 1,260	€ 1,150	$ 1,670	€ 1,500	$ 110	€ 100	$ 1,360	€ 1,200