Capital Stock (Details) - USD ($)		1 Months Ended			3 Months Ended		6 Months Ended
	Dec. 09, 2016	Jun. 30, 2018	Feb. 28, 2018	Jun. 30, 2017	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Stock-based compensation disclosure
Stock compensation expense							$ 2,800,000
Stock options
Stock-based compensation disclosure
Stock options granted to directors (in shares)							5,036,000
2001 Non-Employee Director Stock Plan
Stock-based compensation disclosure
Stock compensation expense						$ 4,000		$ 31,000
2001 Non-Employee Director Stock Plan | Retiring director
Stock-based compensation disclosure
Stock compensation expense		$ 72,000
Compensation Policy for Non-Employee Directors
Stock-based compensation disclosure
Stock compensation expense					$ 100,000	$ 54,000	$ 200,000	$ 156,000
Compensation Policy for Non-Employee Directors | Stock options
Stock-based compensation disclosure
Vesting period							1 year
Stock options granted to directors (in shares)		108,000		128,000
Compensation Policy for Non-Employee Directors | Deferred share units
Stock-based compensation disclosure
Common stock issued to retiring directors (in shares)		95,497	77,012
Vesting period	1 year