Net Income (Loss) Per Share (Computation of Basic Net Income (Loss) Per Share of Common Stock) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended				6 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Sep. 30, 2019	Jun. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Net Income (Loss) Per Share [Abstract]
Net income (loss)	$ (42,622)	$ (58,694)	$ (93,935)	$ (37,517)	$ (101,316)	$ (131,451)
Weighted average common shares outstanding	304,172,412		123,794,511		303,881,424	99,897,191
Minimum shares issuable under purchase contracts	16,465,704		18,429,325		16,465,704	9,214,662
Total weighted average shares outstanding	320,638,116		142,223,836		320,347,128	109,111,853
Basic and diluted net income (loss) per share	$ (0.13)		$ (0.66)		$ (0.32)	$ (1.20)