Schedule of Deferred Tax Assets and Deferred Tax Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Accrued employee benefit plan costs	$ 7,607	$ 5,838
Stock based compensation	786	230
Net operating loss and tax credit carryforwards	102,190	3,941
Restructuring fees not currently deductible for tax purposes	3,113	3,982
Depreciation and amortization		29,160
Other	8,826	3,070
Gross deferred tax assets	122,522	46,221
Less valuation allowance	(106,447)	(43,218)
Net deferred tax assets	16,075	3,003
Depreciation and amortization	(11,149)
Section 1245 recapture	(2,891)	(2,131)
Other	(3,553)	(872)
Gross deferred tax liabilities	(17,593)	$ (3,003)
Net deferred tax assets (liabilities)	$ (1,518)