Stock options - Modification of Existing Canadian Dollar Denominated Options (Details) - 12 months ended Dec. 31, 2018 - Executives And Directors [Member] - Canadian Dollar [Member] shares in Thousands, $ in Thousands	USD ($) shares	$ / shares
Number of Options | shares	648
Expense Recognized | $	$ 112
Stock Option Grant One [Member]
Number of Options | shares	648
Expiration Date	Aug. 18, 2020
Risk free rate	1.90%
Exercise Price | $ / shares		$ 2.43
Share Price | $ / shares		$ 14.14
Expected Life (Years)	2 years 2 months 12 days
Volatility Rate	76.00%
Expense Recognized | $	$ 112