Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Contingency [Line Items]
Increase (decrease) in valuation allowance	$ 4,300	$ (95,100)
Total gross deferred tax assets	13,207	7,766
Unrecognized tax benefits	39	72	$ 3,934
Decrease in prior year unrecognized tax benefits	$ 72	$ 3,934
Federal tax benefit at statutory rate	21.00%	21.00%
Provisional amount related to re-measurement of deferred tax balance, reduction amount	$ 33,000
Tax Cuts and Jobs Act, Accounting complete	true
Federal [Member]
Income Tax Contingency [Line Items]
Net operating loss carryforwards	$ 27,900
Net operating loss carryforwards not subject to expiration	23,100
Net operating loss carryforwards subject to expire	$ 4,800
Operating loss carryforwards, expiration	Begin to expire in 2037
Federal [Member] | Research and Development Tax Credits [Member]
Income Tax Contingency [Line Items]
Tax credits	$ 90
Tax credit, expiration	Begin to expire in 2037
Previously Reported [Member]
Income Tax Contingency [Line Items]
Increase (decrease) in valuation allowance		$ (3,300)