Condensed Consolidated Statements of Operations and Comprehensive Loss (Unaudited) (Parenthetical) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Statement of Comprehensive Income [Abstract]
Research and development, related party	$ 190	$ 3,480	$ 2,293	$ 8,497
General and administrative, related party	$ 0	$ 176	$ 0	$ 357

Amount of selling, general and administrative expenses resulting from transactions, excluding transactions that are eliminated in consolidated or combined financial statements, with related party.

No definition available.

Name:	us-gaap_RelatedPartyTransactionSellingGeneralAndAdministrativeExpensesFromTransactionsWithRelatedParty
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration