Nature of Business and Accounting Policies - Share-Based Compensation (Details)	12 Months Ended
Dec. 31, 2019
Accounting Policies [Abstract]
Percentage of employees eligible for acceleration of equity awards (less than) (percent)	5.00%

Percentage of employees eligible for acceleration of equity awards

No definition available.

Name:	vrtx_Percentageofemployeeseligibleforaccelerationofequityawards
Namespace Prefix:	vrtx_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration