Development and License Agreements - Additional Information (Detail) € in Millions	1 Months Ended	3 Months Ended			12 Months Ended
	Aug. 31, 2019 EUR (€)	Mar. 31, 2020 USD ($)	Mar. 31, 2020 EUR (€)	Mar. 31, 2019 USD ($)	Dec. 31, 2016 EUR (€)	Apr. 30, 2020 USD ($)	Dec. 31, 2019 USD ($)
Licenses Agreements [Line Items]
Payments made relating to the manufacturing of the products		$ 8,100,000		$ 7,800,000
BARDA Agreement
Licenses Agreements [Line Items]
Committed fund receivable		103,200,000
Committed fund receivable		213,900,000
Accounts receivable of billed and unbilled amounts		5,000,000.0					$ 4,200,000
Subsequent Event | BARDA Agreement
Licenses Agreements [Line Items]
Committed fund receivable						$ 116,900,000
Additional committed fund receivable						$ 13,800,000
Cerus Corporation | BARDA Agreement
Licenses Agreements [Line Items]
Co-investment by the company		5,000,000.0
Additional co-investment by the company		9,600,000
Co-investment incurred by the company		$ 1,200,000
Manufacturing and Supply Agreement | Fresenius
Licenses Agreements [Line Items]
Payments made based on the successful achievement of production volumes | €			€ 8.6
Manufacturing and development payments | €	€ 5.5				€ 3.1
Manufacturing and Supply Agreement | Fresenius | Measurement Input, Discount Rate
Licenses Agreements [Line Items]
Manufacturing and development obligations, discount rate					9.72