Basic and Diluted Net Income (Loss) Per Common Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Numerator:
Net income (loss) (1)	$ 35,220	$ 220,439
Weighted-average shares outstanding:
Basic (in shares)	57,339	47,381
Assumed conversion of employee stock grants (in shares)	1,699	2,631
Assumed conversion of warrants (in shares)	0	7,719
Diluted (in shares)	59,038	57,731
Net income (loss) per basic share (in usd per share)	$ 0.61	$ 4.65
Net income (loss) per diluted share (in usd per share)	$ 0.60	$ 3.82
Common stock equivalents that could potentially dilute net income per basic share in the future, but were not included in the computation of diluted earnings per share because the impact would have been antidilutive
Common stock equivalents (in shares)	0	133