Equity Transactions (Details) - USD ($)			1 Months Ended	3 Months Ended		6 Months Ended
	Apr. 28, 2020	Feb. 21, 2020	Feb. 29, 2020	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Class of Stock [Line Items]
Maximum aggregate offering price of securities under shelf registration			$ 250,000
Ordinary shares, nominal value (in usd per share)			$ 0.01	$ 0.01		$ 0.01		$ 0.01
Preferred shares, nominal value (in usd per share)			$ 0.01	$ 0.01		$ 0.01		$ 0.01
Maximum aggregate offering price of ADSs under shelf registration			$ 50,000
Stock transaction issuance costs			$ 328,000
Prepaid expenses and other current assets				$ 32,773,000		$ 32,773,000		$ 4,264,000
February 2020 private placement				(94,000)	$ 60,733,000
Proceeds from the February 2020 private placement						60,639,000	$ 0
Maximum threshold percentage for trigger of convertible preferred stock		9.99%
Additional paid-in capital
Class of Stock [Line Items]
Amortization costs				164,000
Prepaid expenses and other current assets				164,000		$ 164,000
February 2020 private placement				$ (94,000)	$ 60,641,000
Issuance costs		$ 4,361,000
Securities Purchase Agreement
Class of Stock [Line Items]
February 2020 private placement		65,000,000
Proceeds from the February 2020 private placement		$ 60,639,000
American Depositary Receipts | Securities Purchase Agreement
Class of Stock [Line Items]
February 2020 private placement (in shares)		8,680,000
Series A Preferred Stock | Securities Purchase Agreement
Class of Stock [Line Items]
February 2020 private placement (in shares)		488
Shares issued, price per share (in dollars per share)		$ 7.09
American Depositary Shares | Public Offering
Class of Stock [Line Items]
Shares sold in offering	11,630,000
Offering price per share (in dollars per share)	$ 10.75
Gross proceeds from stock offering	$ 125,000,000
Aggregate net proceeds from stock offering	$ 116,974,000