Annual report pursuant to Section 13 and 15(d)

Subsequent Events - Additional Information (Details)

Subsequent Events - Additional Information (Details) $ / shares in Units, $ in Thousands				12 Months Ended
	Feb. 10, 2021 USD ($) $ / shares shares	Feb. 09, 2021 USD ($) $ / shares shares	Feb. 03, 2021 $ / shares shares	Dec. 31, 2020 USD ($) Vote $ / shares shares	Mar. 12, 2021 $ / shares shares	Jan. 28, 2021 $ / shares shares	Jun. 10, 2020 shares	Dec. 31, 2019 $ / shares shares	May 30, 2018 $ / shares shares	Mar. 13, 2018 $ / shares shares	Mar. 12, 2018 $ / shares	Feb. 16, 2018 $ / shares shares	May 18, 2017 $ / shares shares	Nov. 18, 2015 $ / shares shares	Oct. 14, 2015 $ / shares shares
Subsequent Event [Line Items]
Ordinary shares, shares authorized				150,000,000			100,000,000	50,000,000	50,000,000	44,557,606		44,557,606	7,956,715	3,659,453	413,110
Ordinary shares, par value \| $ / shares				$ 0.01				$ 0.01	$ 0.01	$ 0.001	$ 0.0001	$ 0.01	$ 0.01	$ 0.01	$ 0.01
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
Ordinary shares, issued and sold				49,431,028				14,868,973		413,110					413,110
Net proceeds \| $				$ 32,200
Subsequent Event
Subsequent Event [Line Items]
Ordinary shares, shares authorized					300,000,000	150,000,000
Ordinary shares, par value \| $ / shares					$ 0.01	$ 0.01
Subsequent Event \| February SPA
Subsequent Event [Line Items]
Ordinary shares, par value \| $ / shares		$ 0.01
Ordinary shares, issued and sold		17,500,000
Offering price per share \| $ / shares		$ 2.00
Offering closing date		Feb. 12, 2021
Net proceeds \| $		$ 32,200
Percentage of ordinary shares issued to purchase warrants		7.00%
Subsequent Event \| February SPA \| Warrant
Subsequent Event [Line Items]
Number of warrants to purchase ordinary shares		1,225,000
Warrants to purchase ordinary shares, exercise price \| $ / shares		$ 2.50
Warrants expiry date		Feb. 09, 2026
Subsequent Event \| February Underwritten Offering \| Underwriting Agreement
Subsequent Event [Line Items]
Ordinary shares, par value \| $ / shares			$ 0.01
Ordinary shares, issued and sold			34,782,609
Offering price per share \| $ / shares			$ 1.15
Offering closing date			Feb. 08, 2021
Subsequent Event \| February Underwritten Offering \| Pursuant to the Underwriting Agreement
Subsequent Event [Line Items]
Ordinary shares, issued and sold	40,000,000
Additional ordinary shares that can be purchased by underwriter	5,217,391
Net proceeds \| $	$ 42,096
Percentage of ordinary shares issued to purchase warrants	7.00%
Subsequent Event \| February Underwritten Offering \| Pursuant to the Underwriting Agreement \| Warrant
Subsequent Event [Line Items]
Number of warrants to purchase ordinary shares	2,800,000
Warrants to purchase ordinary shares, exercise price \| $ / shares	$ 1.4375
Warrants expiry date	Feb. 03, 2026