CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Statement of Comprehensive Income [Abstract]
Net loss	$ (8,521)	$ (12,437)	$ (29,200)	$ (45,255)
Other comprehensive loss
Unrealized losses on available-for-sale investments, net of taxes	(1,036)	(136)	(3,040)	(493)
Comprehensive loss	(9,557)	(12,573)	(32,240)	(45,748)
Comprehensive loss attributable to noncontrolling interest	(39)		(45)
Total comprehensive loss attributable to Cerus Corporation	$ (9,518)	$ (12,573)	$ (32,195)	$ (45,748)