Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating activities:
Net income (loss)	$ (22,997)	$ (15,752)	$ 13,018
Items not involving cash:
Depreciation and amortization	864	1,038	738
Stock-based compensation	2,161	3,729	760
Deferred tenant inducements	(63)	(63)	(66)
Unrealized foreign exchange (gain) loss	(1,300)	6,902	72
Changes in operating assets and liabilities:
Accounts receivable	121	(107)	209
Prepaid expenses, and other current assets	571	(1,214)	(573)
Prepaid expenses, long term	686	(1,094)
Accounts payable and accrued expenses	547	80	518
Deferred revenue	(157)	(11,622)	(14,410)
Net cash provided by (used in) operating activities	(19,567)	(18,103)	266
Investing activities:
Purchases of property, plant and equipment	(279)	(551)	(1,529)
Purchase of marketable securities	(47,563)		(15,254)
Proceeds from marketable securities		10,745	13,539
Net cash provided by (used in) investing activities	(47,842)	10,194	(3,244)
Financing activities:
Deferred financing fees			(1,533)
Issuance of common shares pursuant to exercise of stock options	132	278	13
Issuance of common shares, net of issuance costs (note 7a)	23,832		42,644
Net cash provided by financing activities	23,964	278	41,124
Effect of exchange rate changes on cash and cash equivalents	1,889	(5,744)	(4,070)
Increase (decrease) in cash and cash equivalents	(41,556)	(13,375)	34,076
Cash and cash equivalents, beginning of year	58,651	72,026	37,950
Cash and cash equivalents, end of year	17,095	58,651	72,026
Supplemental disclosures:
Interest received	341	659	574
Supplemental disclosures of non-cash transactions:
Issuance of common shares on conversion of subscription rights			124
Financing fees included in accounts payable and accrued liabilities			39
Fair value of options exercised on a cashless basis	$ 404	$ 744
Conversion of convertible preferred shares into common shares			$ 102,488