Stock Based Compensation - Summary of Option Activity (Details) (Third Amended and Restated 1997 Stock Option Plan, Stock Options, CAD)	3 Months Ended		12 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2011
Third Amended and Restated 1997 Stock Option Plan | Stock Options
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Options outstanding as of December 31, 2012 (options)	12,337,000
Options granted (options)	2,694,000	4,537,000
Options exercised (options)	(90,000)
Options forfeited, canceled and expired (options)	(751,000)
Options outstanding as of March 31, 2013 (options)	14,190,000
Options exercisable as of March 31, 2013	9,996,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Options outstanding as of December 31, 2012 - Weighted average exercise price	2.74
Options granted - Weighted average exercise price	1.71
Options exercised - Weighted average exercise price	1.70
Options forfeited, canceled and expired - Weighted average exercise price	2.85
Options outstanding as of March 31, 2013 - Weighted average exercise price	2.55
Options exercisable as of March 30, 2013 - Weighted average exercise price exercisable	2.81
Share Based Compensation Arrangement By Share Based Payment Award, Options Outstanding, Weighted Average RemainingTerm, Rollforward [Roll Forward]
Options outstanding as of December 31, 2012 - Aggregate intrinsic value	541,000
Options granted in period - Aggregate intrinsic value	0
Options exercised - Aggregate intrinsic value	18,000
Options forfeited, canceled and expired - Aggegrate intrinsic value	0
Options outstanding as of March 31, 2013 - Aggregate intrinsic value	223,000
Share Based Compensation Arrangement By Share Based Payment Award, Options Outstanding, Weighted Average Remaining Contractual Term, Rollforward [Roll Forward]
Options outstanding as of December 31, 2012 - Weighted average remaining contractual term	6 years		6 years 2 months 12 days
Options granted - Weighted average remaining contractual term	6 years 2 months 12 days
Options exercised - Weighted average remaining contractual term	5 years 10 months 24 days
Options forfeited, canceled and expired - Weighted average remaining contractual term	6 years 2 months 12 days
Options outstanding as of March 31, 2013 - Weighted average remaining contractual term	6 years		6 years 2 months 12 days
Options exercisable as of March 31, 2013 - Weighted average remaining contractual term	5 years 10 months 24 days
Options exercisable - Aggregate intrinsic value	117,000