(Key Assumptions Used to Value Warrants) (Details) - Common Shares	Mar. 31, 2018 year $ / shares	Oct. 31, 2017 year $ / shares
Tranche 1
Class of Warrant or Right [Line Items]
Exercise price (in USD per share)		$ 15.06
Common share price on date of issuance (in USD per share)		$ 14.39
Tranche 2
Class of Warrant or Right [Line Items]
Exercise price (in USD per share)	$ 18.82
Common share price on date of issuance (in USD per share)	$ 18.96
Volatility | Tranche 1
Class of Warrant or Right [Line Items]
Measurement input		0.732
Volatility | Tranche 2
Class of Warrant or Right [Line Items]
Measurement input	0.723
Risk-free interest rate | Tranche 1
Class of Warrant or Right [Line Items]
Measurement input		0.0215
Risk-free interest rate | Tranche 2
Class of Warrant or Right [Line Items]
Measurement input	0.0278
Expected dividend yield | Tranche 1
Class of Warrant or Right [Line Items]
Measurement input		0.00
Expected dividend yield | Tranche 2
Class of Warrant or Right [Line Items]
Measurement input	0.00
Contractual term (in years) | Tranche 1
Class of Warrant or Right [Line Items]
Measurement input | year		7.00
Contractual term (in years) | Tranche 2
Class of Warrant or Right [Line Items]
Measurement input | year	7.00