LIABILITY RELATED TO THE SALE OF FUTURE ROYALTIES (Details) - USD ($)	1 Months Ended	12 Months Ended
	Apr. 30, 2020	Dec. 31, 2020	Jan. 01, 2030	Apr. 10, 2020	Dec. 31, 2019
Liability Related To The Sale Of Future Royalties Line Items [Line Items]
Receivable related to the sale of future royalties		$ 500,000,000			$ 0
Liability related to the sale of future royalties, net of current portion		1,058,225,000			$ 0
Blackstone Group Inc. | Net Revenues from Collaborators
Liability Related To The Sale Of Future Royalties Line Items [Line Items]
Collaborative arrangement, royalties and commercial milestones acquired by collaborator, percent				50.00%
Commercial milestones acquired by collaborator, percent				75.00%
Expected royalty interest payments		1,000,000,000.00
Consideration received	$ 500,000,000.0
Receivable related to the sale of future royalties				$ 500,000,000.0
Liability related to the sale of future royalties, net of current portion		1,071,541,000		$ 1,000,000,000
Interest rate				11.00%
Closing costs		12,955,000
Interest expense including amortization of closing costs		$ 84,496,000
Forecast | Blackstone Group Inc. | Net Revenues from Collaborators
Liability Related To The Sale Of Future Royalties Line Items [Line Items]
Collaborative arrangement, royalties and commercial milestones acquired by collaborator, percent			55.00%