INCOME TAXES - Components of Net Deferred Tax Asset and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Deferred tax assets:
Net operating loss carryforwards	$ 70,960	$ 40,736
Accruals and reserves	24,902	17,576
Depreciation	2,493	2,874
Tax credit carryforwards	15,307	14,896
Other	199	176
Total deferred tax assets	113,861	76,258
Valuation allowances	(28,007)	(27,954)
Total net deferred tax assets	85,854	48,304
Deferred tax liabilities:
Software revenue	(23,859)	(36,510)
Intangibles	(6,103)	(5,748)
Total deferred tax liabilities	(29,962)	(42,258)
Deferred income taxes	$ 55,892	$ 6,046