Collaboration Agreement and Stock Purchase Agreement with Bristol Myers Squibb - Additional Information (Details) - BMS $ in Millions	Jan. 31, 2019 USD ($)
Bristol Myers Squibb Collaboration Agreement and Stock Purchase Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Upfront consideration payment	$ 95.0
Bristol Myers Squibb Collaboration Agreement and Stock Purchase Agreement \| Maximum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Milestone payments eligible to receive	450.0
Bristol Myers Squibb Collaboration Agreement and Stock Purchase Agreement \| IK-175
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Amount eligible to receive in case of exercise of options	50.0
Bristol Myers Squibb Collaboration Agreement and Stock Purchase Agreement \| IK-412
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Amount eligible to receive in case of exercise of options	40.0
Bristol Myers Squibb Collaboration Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Upfront consideration payment	$ 78.7

The amount the Company is eligible to receive if it exercises an option related to a specified program.

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- Definition

The amount the Company is eligible to receive in milestone payments, as part of a collaboration agreement.

+ References

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+ Details

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- 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

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 808
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479402/808-10-50-1

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- Definition

Cash received from collaborators during the current period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 230
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 25
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-25

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