Warrants (Details) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended	12 Months Ended
	Jun. 30, 2015	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Warrant [Abstract]
Warrants sold and issued	7,242,992
Common stock to be issued if warrants are exercised (in shares)	2,172,899
Gross proceeds	$ 77.8
Net proceeds	$ 74.3
Purchase price of common shares	$ 10.70
Purchase price of warrants	0.125
Exercise price for warrants	$ 13.91	$ 13.91
Warrant exercise period	5 years
Maximum beneficial ownership percentage	9.99%
Warrants exercised		0	0	0