401(k) Retirement Savings Plan - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Defined Contribution Plan Disclosure [Line Items]
Percentage of maximum annual contribution per employee	90.00%
Matching contributions amount	$ 0.2	$ 0.2
Defined Contribution Plan, Plan Name [Extensible List]	idya:FourZeroOneKPlanMember	idya:FourZeroOneKPlanMember
Defined Contribution Plan, Sponsor Location [Extensible List]	country:US	country:US
Defined Contribution Plan, Tax Status [Extensible List]	us-gaap:QualifiedPlanMember	us-gaap:QualifiedPlanMember
Maximum
Defined Contribution Plan Disclosure [Line Items]
Matching contributions amount			$ 0.1
Defined Contribution Plan, Plan Name [Extensible List]			idya:FourZeroOneKPlanMember
Defined Contribution Plan, Sponsor Location [Extensible List]			country:US
Defined Contribution Plan, Tax Status [Extensible List]			us-gaap:QualifiedPlanMember