Financing Arrangements - Additional Information (Details) $ in Millions	Jun. 30, 2022 USD ($)
Debt Financing
Royalty Purchase Agreement, milestone payments, achievement of specified net sales milestones, maximum	$ 165.0

Royalty Purchase Agreement, Milestone Payments, Achievement of Specified Net Sales Milestones, Maximum

No definition available.

Name:	bpmc_RoyaltyPurchaseAgreementMilestonePaymentsAchievementOfSpecifiedNetSalesMilestonesMaximum
Namespace Prefix:	bpmc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant