Quarterly report pursuant to Section 13 or 15(d)

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

Shareholders' Equity / (Deficit) - Additional Information (Details) $ / shares in Units, € in Thousands, $ in Thousands						1 Months Ended	9 Months Ended
	Oct. 31, 2020 USD ($) $ / shares shares	Oct. 27, 2020 USD ($) $ / shares shares	Jul. 02, 2020 $ / shares shares	Jun. 05, 2020 $ / shares shares	Jun. 03, 2020 USD ($) $ / shares shares	Jun. 30, 2020 USD ($) $ / shares shares	Sep. 30, 2020 USD ($) Vote $ / shares shares	Jun. 10, 2020 shares	Dec. 31, 2019 $ / shares shares	Sep. 30, 2019 USD ($) shares	Sep. 30, 2019 EUR (€) shares	Aug. 17, 2019 USD ($) shares	Aug. 17, 2019 EUR (€) shares	Jul. 15, 2019 USD ($) shares	Jul. 15, 2019 EUR (€) shares	Dec. 14, 2018 shares	Apr. 27, 2018 $ / shares shares
Class Of Stock [Line Items]
Ordinary shares, shares issued \| shares							21,239,093		14,868,973
Ordinary shares, par value \| $ / shares							$ 0.01		$ 0.01
Proceeds from registered direct offerings, net of transaction costs \| $							$ 8,560
Ordinary shares, shares authorized \| shares							150,000,000	100,000,000	50,000,000
Number of vote per common share \| Vote							1
Common stock rights and preferences							The holders of ordinary shares have no automatic 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 \| shares							100,000,000		100,000,000
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 \| 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 \| shares							19,890										19,890
June 3 SPA
Class Of Stock [Line Items]
Warrants to purchase ordinary shares, exercise price \| $ / shares							$ 0.01
June 3 Offering \| June 3 SPA
Class Of Stock [Line Items]
Ordinary shares, shares issued \| shares					2,971,770
Ordinary shares, par value \| $ / shares					$ 0.01
Purchase 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 \| shares						3,372,686
Ordinary shares, par value \| $ / shares						$ 0.01
Purchase 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 \| Subsequent Event
Class Of Stock [Line Items]
Ordinary shares, shares issued \| shares		15,511,537
Ordinary shares, par value \| $ / shares		$ 0.01
Aggregate gross proceeds from ordinary shares \| $		$ 17,400
Proceeds from registered direct offerings, net of transaction costs \| $	$ 60	$ 15,300
Warrants to purchase ordinary shares, exercise price \| $ / shares	$ 0.8125
Warrants expiry date	Oct. 22, 2025	Oct. 27, 2025
Percentage of ordinary shares issued to purchase warrants	7.00%
October Offering \| Subsequent Event \| Pre-Funded Warrants
Class Of Stock [Line Items]
Ordinary shares, par value \| $ / shares		$ 0.01
Purchase price per share \| $ / shares		$ 0.01
Proceeds from registered direct offerings, net of transaction costs \| $	$ 60
Number of warrants to purchase ordinary shares \| shares	6,284,615	11,411,539
Warrants to purchase ordinary shares, exercise price \| $ / shares		$ 0.64
October Offering \| Subsequent Event \| Warrant
Class Of Stock [Line Items]
Purchase price per share \| $ / shares		$ 0.65
Number of warrants to purchase ordinary shares \| shares	1,884,615	20,192,307
Warrants to purchase ordinary shares, exercise price \| $ / shares		$ 0.65
Warrants expiry date		Oct. 27, 2025
Private Placement \| Securities Purchase Agreement
Class Of Stock [Line Items]
Number of warrants to purchase ordinary shares \| 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 \| shares					1,485,885
Private Placement \| June 30 SPA
Class Of Stock [Line Items]
Number of warrants to purchase ordinary shares \| 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 \| 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 \| 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 \| shares					1,485,885
Supplier
Class Of Stock [Line Items]
Common stock, maximum shares authorized for subscription \| shares																700,000
Maximum subscription units to be accepted \| shares										199,056	199,056	245,493	245,493	17,222	17,222
Issuance of ordinary shares under subscription agreement \| $										$ 1,260		$ 1,670		$ 110
Payment receivable upon common stock subscription agreement										$ 1,260	€ 1,150	$ 1,670	€ 1,500	$ 110	€ 100