SUMMARY OF SIGNIFCANT ACCOUNTING POLICIES - Revision of Previously Issued Consolidated Balance Sheet for Immaterial Adjustment (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020	[1]	Mar. 31, 2020
Change in Accounting Estimate [Line Items]
Other noncurrent liabilities	$ 6,907	$ 6,424		$ 6,424
Total liabilities	227,545	209,495		863,478
Additional paid-in capital	38,217	122,222		122,222
Accumulated deficit	$ (369,253)	$ (369,433)		(369,433)
As Reported
Change in Accounting Estimate [Line Items]
Other noncurrent liabilities				5,539
Total liabilities				862,593
Additional paid-in capital				144,716
Accumulated deficit				(391,042)
Change
Change in Accounting Estimate [Line Items]
Other noncurrent liabilities				885
Total liabilities				885
Additional paid-in capital				(22,494)
Accumulated deficit				$ 21,609

[1] The Consolidated Balance Sheet as of December 31, 2020 has been derived from the audited consolidated financial statements, revised to reflect the Company’s fair value change of its underlying warrants. Refer to Note 1—Summary of Significant Accounting Policies, see the section titled Revision of Previously Issued Consolidated Financial Statements for Immaterial Adjustment for further information.