Quarterly report pursuant to Section 13 or 15(d)

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

Shareholders' (Deficit) / Equity - Additional Information (Details) $ / shares in Units, € in Thousands, $ in Thousands				1 Months Ended	6 Months Ended
	Jul. 02, 2020 $ / shares shares	Jun. 05, 2020 $ / shares shares	Jun. 03, 2020 USD ($) $ / shares shares	Jun. 30, 2020 USD ($) $ / shares shares	Jun. 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				17,852,149	17,852,149		14,868,973
Ordinary shares, par value \| $ / shares				$ 0.01	$ 0.01		$ 0.01
Proceeds from registered direct offering, net of transaction costs \| $					$ 4,328
Ordinary shares, shares authorized				150,000,000	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 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		$ 0.01
Undesignated preferred shares, authorized				100,000,000	100,000,000		100,000,000
Ordinary Shares
Class Of Stock [Line Items]
Number of warrants to purchase ordinary shares				19,890	19,890										19,890
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										19,890
Warrants to purchase ordinary shares, exercise price \| $ / shares				$ 18.85	$ 18.85										$ 18.85
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
Purchase price per share \| $ / shares			$ 1.6825
Aggregate gross proceeds from ordinary shares \| $			$ 5,000
Proceeds from registered direct offering, 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	3,372,686
Ordinary shares, par value \| $ / shares				$ 0.01	$ 0.01
Purchase price per share \| $ / shares				$ 1.4825	1.4825
Aggregate gross proceeds from ordinary shares \| $				$ 5,000
Proceeds from registered direct offering, net of transaction costs \| $				$ 4,400
Warrants closing date				Jul. 02, 2020
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	$ 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	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
Maximum subscription units to be accepted								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