Development and License Agreements - Additional Information (Detail) € in Millions	1 Months Ended	3 Months Ended		9 Months Ended			12 Months Ended
	Jun. 30, 2016 USD ($)	Sep. 30, 2016 USD ($)	Sep. 30, 2015 USD ($)	Sep. 30, 2016 USD ($)	Sep. 30, 2016 EUR (€)	Sep. 30, 2015 USD ($)	Dec. 31, 2016 EUR (€)	Sep. 30, 2016 EUR (€)	Dec. 31, 2015 USD ($)	Dec. 31, 2015 EUR (€)
Licenses Agreements [Line Items]
Manufacturing and development obligations - current									$ 3,282,000
Manufacturing and development obligations - non-current		$ 5,004,000		$ 5,004,000					4,542,000
Payments made relating to the manufacturing of the products		4,800,000	$ 3,000,000	11,800,000		$ 12,500,000
Amounts due from Fresenius		500,000		500,000					200,000
Contracts revenue		261,000		$ 261,000
BARDA Agreement
Licenses Agreements [Line Items]
Committed fund receivable	$ 30,800,000
Committed fund receivable	180,500,000
Period of agreement				5 years	5 years
Contracts revenue			$ 0			$ 0
Other current assets
Licenses Agreements [Line Items]
Research and development assets		3,100,000		$ 3,100,000					4,100,000
Other assets
Licenses Agreements [Line Items]
Manufacturing efficiency assets		2,100,000		2,100,000					2,400,000
Fresenius
Licenses Agreements [Line Items]
Allocated amount for research and development activities		4,800,000		4,800,000
Manufacturing efficiency activity cost		2,400,000		2,400,000
Cerus Corporation | BARDA Agreement
Licenses Agreements [Line Items]
Co-investment by the company	$ 14,500,000
Manufacturing and Supply Agreement
Licenses Agreements [Line Items]
Accrual for manufacturing of entity products		3,100,000		3,100,000					2,500,000
Manufacturing and Supply Agreement | Fresenius
Licenses Agreements [Line Items]
Accrual for manufacturing and development of entity products		$ 5,000,000		$ 5,000,000				€ 4.5	$ 7,800,000	€ 7.2
Manufacturing and development obligations, discount rate				9.72%	9.72%
Manufacturing and development payments				$ 3,400,000	€ 3.1
Manufacturing and development obligations - current | €										3.0
Manufacturing and development obligations - non-current | €										€ 4.2
Scenario Forecast | Manufacturing and Supply Agreement | Fresenius
Licenses Agreements [Line Items]
Payments made based on the successful achievement of production volumes | €							€ 8.6