Temporary Equity, Stock Issued During Period, Shares, New Issues

No definition available.

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Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Upfront Payment Received

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The aggregate amount of receivables to be collected from related parties where one party can exercise control or significant influence over another party; including affiliates, owners or officers and their immediate families, pension trusts, and so forth, at the financial statement date. which are usually due within one year (or one business cycle).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
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+ Details

Name:	us-gaap_DueFromRelatedPartiesCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_RelatedPartyTransactionLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Cash received on stock transaction after deduction of issuance costs.

+ References

No definition available.

+ Details

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

- Definition

The number of shares issued or sold by the subsidiary or equity method investee per stock transaction.

+ References

No definition available.

+ Details

Name:	us-gaap_SaleOfStockNumberOfSharesIssuedInTransaction
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Per share amount received by subsidiary or equity investee for each share of common stock issued or sold in the stock transaction.

+ References

No definition available.

+ Details

Name:	us-gaap_SaleOfStockPricePerShare
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

Number of shares issued during the period as a result of the conversion of convertible securities.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
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+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Value of new stock classified as temporary equity issued during the period.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

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- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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Balance Type:
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- Details

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- Details

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- Details

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- Details

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Balance Type:
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- Details

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- Details

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Related-party Transactions (Details) - USD ($)			1 Months Ended
Related-party Transactions (Details) - USD ($)	Jul. 22, 2019	Feb. 01, 2017	Jul. 31, 2019	Jul. 31, 2016	Dec. 31, 2019	Dec. 31, 2018
Celgene License Agreement
Related Party Transaction [Line Items]
Non-refundable upfront payment received for research agreement	$ 50,000,000
Celegene Collaborative Arrangement
Related Party Transaction [Line Items]
Non-refundable upfront payment received for research agreement				$ 225,000,000
Series B-1 Convertible Preferred Stock \| Celegene Collaborative Arrangement
Related Party Transaction [Line Items]
Issuances of convertible preferred stock (in shares)				10,448,100
Issuances of convertible preferred stock				$ 36,100,000
Celgene Corporation \| Celgene License Agreement \| Celgene License Agreement
Related Party Transaction [Line Items]
Non-refundable upfront payment received for research agreement			$ 50,000,000
Reimbursable expenses due from Celgene					$ 700,000	$ 0
Celgene Corporation \| Celgene Collaboration Agreement \| Celegene Collaborative Arrangement
Related Party Transaction [Line Items]
Non-refundable upfront payment received for research agreement				$ 225,000,000
Celgene Corporation \| Celgene Collaboration Agreement \| Series B-1 Convertible Preferred Stock \| Celegene Collaborative Arrangement
Related Party Transaction [Line Items]
Issuances of convertible preferred stock (in shares)				10,448,100
Issuances of convertible preferred stock				$ 36,100,000
Celgene Corporation \| IPO \| Celgene Collaboration Agreement \| Common Stock
Related Party Transaction [Line Items]
Stock converted upon completion of IPO (in shares)		2,831,463
Affiliated Entity \| Celgene Corporation \| IPO \| Celgene Collaboration Agreement \| Common Stock
Related Party Transaction [Line Items]
Sale of stock, number of shares issued (in shares)		625,000
Sale of stock, price per share (USD per share)		$ 16.00
Proceeds from IPO, net of discounts, commissions, and other offering expenses		$ 10,000,000