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, 2013	Dec. 31, 2016
Income Taxes [Line Items]
Net operating loss carryforwards		$ 124,115	$ 106,430
Deferred tax assets operating loss carryforwards without expire date		128,000
Research and development credit carryforwards		$ 35,130	33,684
Net operating loss carryforwards, expiration date		2039
Accumulated excess tax benefit recognised as deferred tax asset		$ 605	0
Uncertain Tax Positions Adjustment		0	$ 0	$ 0
Increase (decrease) in deferred tax assets		$ 15,400
Effective income tax rate		21.00%	21.00%	34.00%
Increase (decrease) in deferred revenue			$ (146)	$ (6,389)
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		21.00%	35.00%
Change in tax rate in income tax expense benefit		$ 67,000
Research Tax Credit Carryforward
Income Taxes [Line Items]
Research and development credit carryforwards		35,000
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		$ 470,000
Net operating loss carryforwards, expiration date		2039
Federal and State
Income Taxes [Line Items]
Deferred tax assets operating loss carryforwards with expire date		$ 342,000
State and Local Jurisdiction
Income Taxes [Line Items]
Net operating loss carryforwards		$ 404,000