Development and License Agreements - Additional Information (Detail) € in Millions	1 Months Ended	12 Months Ended
	Jun. 30, 2016 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2016 EUR (€)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2016 EUR (€)	Dec. 31, 2015 EUR (€)
Licenses Agreements [Line Items]
Royalty payments on products		$ 0		$ 1,900,000	$ 2,500,000
Manufacturing and development obligations - current				3,282,000
Manufacturing and development obligations - non-current		4,770,000		4,542,000
Payments made relating to the manufacturing of the products		16,100,000		14,900,000	$ 19,100,000
Amounts due from Fresenius		$ 300,000		200,000
BARDA Agreement
Licenses Agreements [Line Items]
Committed fund receivable	$ 41,600,000
Committed fund receivable	185,000,000
Period of agreement		5 years	5 years
Accounts receivable		$ 1,000,000		0
Other current assets
Licenses Agreements [Line Items]
Research and development assets		900,000		4,100,000
Other assets
Licenses Agreements [Line Items]
Research and development assets		2,000,000
Manufacturing efficiency assets		2,100,000		2,400,000
Fresenius
Licenses Agreements [Line Items]
Allocated amount for research and development activities		4,800,000
Manufacturing efficiency activity cost		2,400,000
Cerus Corporation | BARDA Agreement
Licenses Agreements [Line Items]
Co-investment by the company	$ 15,000,000
Manufacturing and Supply Agreement
Licenses Agreements [Line Items]
Accrual for manufacturing of entity products		$ 3,000,000		2,500,000
Manufacturing and Supply Agreement | Fresenius
Licenses Agreements [Line Items]
Payments made based on the successful achievement of production volumes | €			€ 8.6
Manufacturing and development obligations, discount rate		9.72%	9.72%
Manufacturing and development payments		$ 3,400,000	€ 3.1
Accrual for manufacturing and development of entity products		$ 4,800,000		$ 7,800,000		€ 4.5	€ 7.2
Manufacturing and development obligations - current | €							3.0
Manufacturing and development obligations - non-current | €							€ 4.2