Summary of Significant Accounting Policies - Schedule of Impacts to Condensed Consolidated Balance Sheet Upon Adoption of 842 Guidance (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Assets
Property and equipment, net	$ 44,865	$ 127,198
Finance lease right-of-use assets	44,536	0
Liabilities, stockholders’ equity and non-controlling interests
Finance lease liabilities, current	12,071	0
Deferred rent	0	3,038
Finance lease liabilities, non-current	43,780	0
Accumulated deficit	(637,158)	$ (715,827)
Derecognition Build to Suit Lease Assets [Member] \| Building Shell [Member]
Assets
Property and equipment, net	(53,880)
Derecognition Build to Suit Lease Assets Accumulated Depreciation [Member] \| Building Shell [Member]
Assets
Property and equipment, net	13,476
Leasehold Improvements Accumulated Depreciation [Member]
Assets
Property and equipment, net	(38,877)
Recognition Finance Lease Assets [Member]
Assets
Finance lease right-of-use assets	49,597
Recognition Operating Lease Assets [Member]
Assets
Other assets	730
Derecognition Deferred Rent Current [Member]
Liabilities, stockholders’ equity and non-controlling interests
Accrued and other current liabilities	(619)
Derecognition Build to Suit Lease Liabilities Current [Member]
Liabilities, stockholders’ equity and non-controlling interests
Accrued and other current liabilities	(545)
Recognition Operating Lease Liabilities Current [Member]
Liabilities, stockholders’ equity and non-controlling interests
Accrued and other current liabilities	404
Recognition Finance Lease Liabilities Current [Member]
Liabilities, stockholders’ equity and non-controlling interests
Finance lease liabilities, current	11,499
Derecognition Build to Suit Lease Liabilities Non Current [Member]
Liabilities, stockholders’ equity and non-controlling interests
Long-term portion of lease obligations	(95,613)
Derecognition Deferred Rent Non Current [Member]
Liabilities, stockholders’ equity and non-controlling interests
Deferred rent	(3,038)
Recognition Finance Lease Liabilities Non Current [Member]
Liabilities, stockholders’ equity and non-controlling interests
Finance lease liabilities, non-current	49,884
Recognition Operating Lease Liabilities Non Current [Member]
Liabilities, stockholders’ equity and non-controlling interests
Other long-term liabilities	250
Cumulative Decrease to Accumulated Deficit [Member]
Liabilities, stockholders’ equity and non-controlling interests
Accumulated deficit	$ 8,688

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