Income Taxes - Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Deferred tax assets:
Net operating loss carryforwards	$ 95,611	$ 47,451
Stock-based compensation	18,117	26,838
Reserves and accruals	56,111	18,409
Goodwill	5,666	9,855
Intangible assets	3,364	3,978
Tax credit carryforwards	7,499	2,483
Other	637	82
Total deferred tax assets	187,005	109,096
Valuation allowance	(140,623)	(75,308)
Deferred tax assets – net of valuation allowance	46,382	33,788
Deferred tax liabilities:
Internally developed software	(19,340)	(21,436)
Accrued receivables	(13,838)	0
Servicing fees	(8,630)	(6,445)
Depreciation and amortization	(3,047)	(5,907)
Other	(1,527)	0
Total deferred tax liabilities	(46,382)	(33,788)
Deferred tax asset (liability) – net	$ 0	$ 0