Shareholder Equity - Share-Based Payments (Details) - shares	1 Months Ended			3 Months Ended
	Dec. 31, 2018	Aug. 31, 2018	Sep. 30, 2016	Mar. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock option to purchase shares (in shares)	425,000		650,000	2,110,115
Outstanding classified as inducement awards (in shares)	3,941,947			5,688,562
Inducement awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding classified as inducement awards (in shares)				1,937,500
Chief Executive Officer | Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock option to purchase shares (in shares)		1,350,000