Convertible Senior Notes - Capped Call and Common Stock Forward (Details) $ / shares in Units, $ in Millions	1 Months Ended	3 Months Ended
	Mar. 31, 2019 USD ($) $ / shares shares	Mar. 31, 2019 USD ($) $ / shares shares
Capped Call and Common Stock Forward
Share Price	$ 2.35	$ 2.35
Common stock shares issued | shares	10,000,000	10,000,000
Capped Call
Capped Call and Common Stock Forward
Capped call options amount | $	$ 16.0	$ 16.0
Cap price	$ 3.82	$ 3.82
Premium (as a percent)		100.00%
Share Price	$ 1.91	$ 1.91
Common Stock Forward
Capped Call and Common Stock Forward
Common stock shares issued | shares		14,397,906
Net cost incurred | $		$ 27.5