INCOME TAXES - Significant Components of Company's Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Deferred tax assets:
Net operating loss	$ 215,915	$ 209,795
Tax credits	76,504	58,724
Lease liabilities	20,213	23,203
Stock-based compensation	14,899	22,181
Capitalized software cost	59,487	39,582
Other	5,531	5,013
Total deferred tax assets	392,549	358,498
Valuation allowance	(324,422)	(282,337)	$ (204,182)	$ (112,389)
Total deferred tax assets, net	68,127	76,161
Deferred tax liabilities:
Lease assets	(16,376)	(19,296)
Acquired intangible assets	(32,120)	(39,497)
Contract cost asset	(16,868)	(15,324)
Prepaid and accrued expenses	(3,184)	(2,897)
Other	(1,201)	(1,522)
Total deferred tax liabilities	(69,749)	(78,536)
Total	$ (1,622)	$ (2,375)