Shareholders' Equity and Capital Stock - options activity (Details) - $ / shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Options Rollforward
Outstanding, Beginning Balance	9,974,407	8,468,614	9,273,659
Granted, Options	3,062,542	2,384,052	1,136,776
Exercised, Options	(16,620)	(608,531)	(1,623,139)
Forfeited, Options	(788,883)	(258,918)	(303,612)
Expired, Options	(2,482,512)	(10,810)	(15,070)
Outstanding Ending Balance, Options	9,748,934	9,974,407	8,468,614
Outstanding, Beginning Balance, Weighted-average exercise price	$ 0.88	$ 1.12	$ 1.19
Granted, Weighted-average exercise price	0.57	0.67	0.93
Exercised, Weighted-average exercise price	0.58	0.66	0.83
Forfeited, Weighted-average exercise price	0.70	1.09	1.45
Expired, Weighted-average exercise price	1.56	0.64	0.82
Outstanding Ending Balance, Weighted-average exercise price	0.63	$ 0.88	$ 1.12
Grant date intrinsic value	$ 0