Quarterly Financial Data (unaudited) - Quarterly Financial Data (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenues:
Revenues	$ 1,627,820	$ 1,538,271	$ 1,524,485	$ 1,515,107	$ 1,413,265	$ 949,828	$ 941,293	$ 858,435	$ 6,205,683	$ 4,162,821	$ 3,047,597
Costs and expenses:
Cost of sales	203,101	186,182	184,520	162,497	185,012	131,914	135,740	95,092	736,300	547,758	409,539
Research and development expenses	466,584	493,497	420,928	448,528	480,011	555,948	379,091	339,490	1,829,537	1,754,540	1,416,476
Sales, general and administrative expenses	211,843	184,551	191,804	182,258	195,277	159,674	156,502	147,045	770,456	658,498	557,616
Change in fair value of contingent consideration	500	1,800	9,200	1,600	1,500	2,959	0	0	13,100	4,459	0
Total costs and expenses	882,028	866,030	806,452	794,883	861,800	850,495	671,333	581,627	3,349,393	2,965,255	2,412,447
Income from operations	745,792	672,241	718,033	720,224	551,465	99,333	269,960	276,808	2,856,290	1,197,566	635,150
Interest income	2,320	3,100	4,243	12,576	12,359	17,628	18,076	15,615	22,239	63,678	38,352
Interest expense	(16,288)	(13,856)	(13,871)	(14,136)	(14,249)	(14,548)	(14,837)	(14,868)	(58,151)	(58,502)	(72,471)
Other income (expense), net	156,799	84,386	116,365	(61,130)	127,375	(31,747)	53,939	42,610	296,420	192,177	(790)
Income before provision for (benefit from) income taxes	888,623	745,871	824,770	657,534	676,950	70,666	327,138	320,165	3,116,798	1,394,919	600,241
Provision for income taxes	284,433	78,437	(12,500)	54,781	93,716	13,148	59,711	51,534	405,151	218,109	(1,486,862)
Net income attributable to Vertex	$ 604,190	$ 667,434	$ 837,270	$ 602,753	$ 583,234	$ 57,518	$ 267,427	$ 268,631	$ 2,711,647	$ 1,176,810	$ 2,096,896
Net income:
Basic ( in usd per share)	$ 2.32	$ 2.56	$ 3.22	$ 2.32	$ 2.26	$ 0.22	$ 1.04	$ 1.05	$ 10.44	$ 4.58	$ 8.24
Diluted (in usd per share)	$ 2.30	$ 2.53	$ 3.18	$ 2.29	$ 2.23	$ 0.22	$ 1.03	$ 1.03	$ 10.29	$ 4.51	$ 8.09
Shares used in per share calculations:
Basic (in shares)	260,038	260,392	259,637	259,815	258,003	256,946	256,154	255,695	259,841	256,728	254,292
Diluted (in shares)	263,106	264,079	263,403	263,515	262,108	260,473	259,822	260,175	263,396	260,673	259,185
Product revenues, net
Revenues:
Revenues	$ 1,626,920	$ 1,536,271	$ 1,524,485	$ 1,515,107	$ 1,413,265	$ 949,828	$ 940,380	$ 857,253	$ 6,202,783	$ 4,160,726	$ 3,038,325
Collaborative and royalty revenues
Revenues:
Revenues	$ 900	$ 2,000	$ 0	$ 0	$ 0	$ 0	$ 913	$ 1,182	$ 2,900	$ 2,095	$ 9,272