Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands		12 Months Ended
	Jan. 02, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2013
Income Taxes [Line Items]
Net operating loss carryforwards			$ 106,430	$ 89,098
Research and development credit carryforwards			$ 33,684	32,395
Net operating loss carryforwards, expiration date			2038
Accumulated excess tax benefit recognised as deferred tax asset			$ 0	$ 0
Increase (decrease) in deferred tax assets			$ (2,900)
Effective income tax rate			21.00%	34.00%	34.00%
Increase (decrease) in deferred revenue			$ (146)	$ (6,389)	$ (6,861)
Revenues				15,900
Deferred revenue				$ 41,500
Difference between revenue guidance in effect before and after topic 606
Income Taxes [Line Items]
Increase (decrease) in deferred revenue	$ 8,100
ASU 2016-09
Income Taxes [Line Items]
Accumulated excess tax benefit recognised as deferred tax asset					10,200
Accumulated Deficit | ASU 2016-09
Income Taxes [Line Items]
Cumulative-effect adjustment from adoption of ASU 2016-09					$ 122
Tax Cuts And Jobs Act of 2017
Income Taxes [Line Items]
Effective income tax rate			35.00%
Change in tax rate in income tax expense benefit			$ 67,000
Tax Cuts And Jobs Act of 2017 | Scenario, Forecast
Income Taxes [Line Items]
Effective income tax rate		21.00%
Research Tax Credit Carryforward
Income Taxes [Line Items]
Research and development credit carryforwards			34,000
Net Operating Loss Carryforwards
Income Taxes [Line Items]
Increase (decrease) in deferred tax assets						$ (11,200)
General Business Credits
Income Taxes [Line Items]
Increase (decrease) in deferred tax assets						$ (636)
Domestic Tax Authority
Income Taxes [Line Items]
Net operating loss carryforwards			$ 403,000
Net operating loss carryforwards, expiration date			2038
Federal and State
Income Taxes [Line Items]
Net operating loss carryforwards			$ 344,000