Description of Business - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands		6 Months Ended
	Jun. 29, 2020	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Proceeds from equity offering, net of issuance costs paid		$ 86,816	$ 0
Estimated issuance costs unpaid		534	0
Accumulated deficit		(700,666)		$ (662,191)
Net cash used in operating activities		(29,117)	$ (29,905)
Underwritten Public Offering
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Shares issued	8,521,500
Proceeds from equity offering, net of issuance costs paid	$ 90,700
Underwriting discounts, commissions and other offering expenses	$ 4,400
Underwritten Public Offering | Accounts Payable and Accrued Expenses
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Estimated issuance costs unpaid		$ 500
Underwritten Public Offering | Public
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Shares issued	4,811,500
Share price	$ 9.50
Underwritten Public Offering | Shares Sold to Public upon full Exercise of Underwriters Option to Purchase Additional Shares
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Share price	$ 9.50
Shares sold to public upon full exercise of underwriters’ option to purchase additional shares	1,111,500
Underwritten Public Offering | Dr. Patrick Soon-Shiong
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Shares issued	3,710,000
Share price	$ 12.12