Commitments and Contingencies - Additional Information (Detail) € in Millions, $ in Millions	3 Months Ended			12 Months Ended
	Mar. 31, 2018 USD ($)	Mar. 31, 2018 EUR (€)	Mar. 31, 2017 USD ($)	Dec. 31, 2013 USD ($)	Mar. 31, 2018 EUR (€)	Dec. 31, 2017 USD ($)
Loss Contingencies [Line Items]
Incentive awarded to the company by the State of Connecticut, total	$ 11.5			$ 11.5
Incentive awarded to the company by the State of Connecticut, non-interest bearing loans	8.0			8.0
Incentive awarded to the company by the State of Connecticut, grants	$ 3.5			$ 3.5
Non-interest bearing incentive loan term	10 years	10 years
Forgiveness awarded to the company by the state of Connecticut	$ 7.0
Incentive awarded to the company by the State of Connecticut, revenue recognized	0.4		$ 0.3
Incentive awarded to the company by the State of Connecticut, deferred revenue	5.7					$ 4.4
Ackermans & van Haaren NV, Mr. Jozef Gielen and Kapimar Comm.V | Share Purchase Agreement
Loss Contingencies [Line Items]
Aggregate consideration payment for purchase of shares	43.1	€ 35.0
Termination fee payable	6.2				€ 5.0
Termination fee receivable	12.3				10.0
Additional reimbursement amount receivable	$ 6.2				€ 5.0