License Agreements - Syros (Details) $ / shares in Units, $ in Thousands, shares in Millions	1 Months Ended	3 Months Ended		12 Months Ended
	Jan. 31, 2018 USD ($) item	Mar. 31, 2022 USD ($)	Mar. 31, 2021 USD ($)	Dec. 31, 2018 USD ($) $ / shares shares	Dec. 31, 2021 USD ($)
License agreements
Long term investments		$ 174,681			$ 221,266	[1]
Research and development expense		353,373	$ 306,896
Unrealized gain (loss) on long term investments		(46,585)	(27,709)
Syros Pharmaceuticals, Inc.
License agreements
Fair market value of our long term investments		$ 1,100			$ 3,100
Ownership percentage (as a percent)		2.00%
Unrealized gain (loss) on long term investments		$ (1,900)	$ (3,200)
Syros Pharmaceuticals, Inc.
License agreements
Number of program targets | item	7
Syros Pharmaceuticals, Inc. | Maximum
License agreements
Target selection and option exercise fee payment	$ 54,000
Syros Pharmaceuticals, Inc. | Development and Regulatory Milestones | Maximum
License agreements
Additional milestone payments under the license agreement	50,000
Syros Pharmaceuticals, Inc. | Commercialization Milestones | Maximum
License agreements
Additional milestone payments under the license agreement	$ 65,000
Stock purchase agreement | Syros Pharmaceuticals, Inc.
License agreements
Purchase of common stock under Stock Purchase Agreement (in shares ) | shares				0.8
Purchase price of common stock				$ 10,000
Per share price | $ / shares				$ 12.61
Amended stock purchase agreement | Syros Pharmaceuticals, Inc.
License agreements
Purchase of common stock under Stock Purchase Agreement (in shares ) | shares				0.1
Purchase price of common stock				$ 1,400
Per share price | $ / shares				$ 9.55

[1] The condensed consolidated balance sheet at December 31, 2021 has been derived from the audited consolidated financial statements at that date.