Share-based compensation and stockholders' equity - Narrative (Details) $ / shares in Units, shares in Millions		3 Months Ended		6 Months Ended
	Sep. 17, 2024 USD ($) $ / shares shares	Jun. 30, 2025 USD ($) $ / shares shares	Mar. 31, 2024 USD ($) increment	Jun. 30, 2025 USD ($) $ / shares shares	Mar. 31, 2025 USD ($)	Dec. 31, 2024 USD ($)	Aug. 30, 2024 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Nonvested options forfeited (in shares)				0.3
Repurchases of common stock \| $		$ 6,900,000
Warrant liability \| $		9,600,000		$ 9,600,000		$ 16,200,000
2025 Share Repurchase Program
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share repurchase program, authorized, amount \| $					$ 50,000,000
Repurchases of common stock \| $		$ 6,900,000		$ 6,900,000
Treasury stock, shares, acquired (in shares)		1.1		1.1
Shares average cost price (in dollars per share) \| $ / shares		$ 6.12		$ 6.12
Remaining authorized amount \| $		$ 43,100,000		$ 43,100,000
Series I Warrants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Class of warrant or right, number of securities called by warrants or rights (in shares)							1.0
Series II Warrants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Class of warrant or right, number of securities called by warrants or rights (in shares)							1.5
Subscription Agreement
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Sale of stock, number of shares issued in transaction (in shares)	1.1
Consideration received on transaction \| $	$ 10,000,000
Sale of stock, price per share (in dollars per share) \| $ / shares	$ 8.98
Liabilities, fair value adjustment \| $	$ 1,600,000
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options granted (in shares)				1.6
Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity instruments other than options granted (in shares)				2.5
Equity instruments other than options, forfeited in period (in shares)				0.2
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity instruments other than options granted (in shares)				0.3
Award performance period				1 year
Award vesting period			3 years
Equity instruments other than options, forfeited in period (in shares)				0.0
Long-Term Incentive Award
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted long-term incentive award \| $			$ 8,000,000
Award vesting period			5 years
Performance Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period			5 years
Other Equity Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of vesting increments \| increment			3

Emergent BioSolutions Inc. 10-Q