NET LOSS PER SHARE - Earnings Per Share, Basic and Diluted (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended						9 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Dec. 31, 2020	Dec. 31, 2019
Earnings Per Share [Abstract]
Net loss	$ (40,225)	$ (38,413)	$ (41,913)	$ (47,071)	$ (40,932)	$ (34,265)	$ (120,551)	$ (122,268)
Weighted average common shares outstanding - basic and diluted (in shares)	106,641			99,922			104,961	99,082
Net loss per share:
Basic and diluted (in dollars per share)	$ (0.38)			$ (0.47)			$ (1.15)	$ (1.23)