Consolidated Statement of Shareholders' Equity (Unaudited) - USD ($) $ in Thousands	Total		Convertible Preferred Shares [Member]	Common Shares [Member]	Additional Paid-in Capital [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive Loss [Member]	[1]
Balance at Dec. 31, 2016	$ 63,901			$ 173,246	$ 34,326	$ (142,681)	$ (990)
Balance (in Shares) at Dec. 31, 2016				17,930,590
Net loss	(30,704)					(30,704)
Stock-based compensation expense	2,460				2,460
Issued pursuant to exercise of stock options	177			$ 595	(415)	(3)
Issued pursuant to exercise of stock options (in Shares)				67,830
Issuance of warrants	100				100
Balance at Dec. 31, 2017	35,934			$ 173,841	36,471	(173,388)	(990)
Balance (in Shares) at Dec. 31, 2017				17,998,420
Net loss	(3,755)					(3,755)
Issued (cancelled) pursuant to exchange agreement (note 9a)			$ 21,825	$ (21,825)
Issued (cancelled) pursuant to exchange agreement (note 9a) (in Shares)			2,868,000	(2,868,000)
Cancelled pursuant to termination of collaboration agreement (note 9b)	(4,470)			$ (4,470)
Cancelled pursuant to termination of collaboration agreement (note 9b) (in Shares)				(1,000,000)
Stock-based compensation expense	670				670
Issued pursuant to exercise of stock options	$ 119			$ 341	(222)
Issued pursuant to exercise of stock options (in Shares)	84,668	[2]		40,881
Balance at Mar. 31, 2018	$ 28,498		$ 21,825	$ 147,887	$ 36,919	$ (177,143)	$ (990)
Balance (in Shares) at Mar. 31, 2018			2,868,000	14,171,301

[1] Our accumulated other comprehensive loss is entirely related to historical cumulative translation adjustments from the application of U.S. dollar reporting when the functional currency of the Company was the Canadian dollar.

[2] During the three months ended March 31, 2018, 13,374 stock options were exercised for the same number of common shares for cash (three months ended March 31, 2017 – 62,397). In the same period, the Company issued 27,507 common shares (three months ended March 31, 2017 – 3,693) for the cashless exercise of 71,294 stock options (three months ended March 31, 2017 – 5,524).