Subsequent Events - Public Offering (Details) - USD ($) $ / shares in Units, $ in Thousands		6 Months Ended
	Jul. 31, 2018	Jun. 30, 2018
Subsequent Events
Gross proceeds from sale of ordinary shares		$ 22,784
Subsequent Event | Public offering
Subsequent Events
Number of shares issued	18,181,818
Shares issued price per share	$ 2.75
Gross proceeds from sale of ordinary shares	$ 50,000
Net proceeds from sale of ordinary shares	$ 46,100