Condensed consolidated statements of cash flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Operating activities
Net loss	$ (17,612)	$ (11,162)
Non-cash items and reclassifications:
Change in fair value of derivative liabilities	(73)	(6)
Stock-based compensation	915	721
Foreign exchange loss and others	48	425
Changes in operating assets and liabilities:
Receivable, prepayments and deposits	(771)	(445)
Accounts payable and other liabilities	3,705	(1,232)
Cash used in operating activities	(13,788)	(11,699)
Investing activities
Purchase of investments	(34,557)
Proceeds from maturity of investments	31,575	12,094
Purchase of property and equipment	(320)	(6)
Cash (used in) provided by investing activities	(3,302)	12,088
Financing activities
Proceeds from exercise of stock options	4	96
Payment on capital lease obligation	(1)
Public offering costs		(76)
Cash provided by financing activities	3	20
Effect of exchange rate changes on cash and cash equivalents	31	(399)
Net change in cash and cash equivalents during the period	(17,056)	10
Cash and cash equivalents, beginning of period	39,526	14,906
Cash and cash equivalents, end of period	22,470	14,916
Supplemental disclosure of cash flow information:
Interest received	$ 249	27
Non-cash financing activities:
Accrued offering costs		$ 11