CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Current assets:
Cash	$ 104,206	$ 131,468
Prepaid expenses and other current assets	10,467	5,197
Total current assets	114,673	136,665
Property and equipment, net	2,936	2,344
Equity method investment (Note 5)	8,494	7,847
Other assets	32	32
Total assets	126,135	146,888
Current liabilities:
Accounts payable	9,051	4,721
Accrued expenses	7,814	4,708
Total current liabilities	16,865	9,429
Warrant liability		4,021
Other long-term liabilities	1,454	1,467
Total liabilities	18,319	14,917
Commitments and contingencies (Note 13)
Shareholders' equity:
Common shares, no par value; 200,000,000 shares authorized as of March 31, 2018 and December 31, 2017; 38,607,017 and 36,057,748 shares issued and outstanding as of March 31, 2018 and December 31, 2017, respectively	367,730	311,061
Additional paid-in capital	28,194	23,556
Accumulated deficit	(288,108)	(202,646)
Total shareholders' equity	107,816	131,971
Total liabilities and shareholders? equity	$ 126,135	$ 146,888