Accounts payable and accrued liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Payables and Accruals [Abstract]
Accounts payable	$ 3,450	$ 6,296
Accrued expenses	5,788	5,743
Accrued compensation and benefits	2,028	2,923
Other current liabilities	16	40
Total accounts payable and accrued liabilities	$ 11,282	$ 15,002