Commitments and Contingencies - Additional Information (Detail) $ in Millions	1 Months Ended	9 Months Ended	12 Months Ended
	May 31, 2019 ft²	Sep. 30, 2019 l	Dec. 31, 2018 USD ($)
Maximum [Member]
Commitments and Contingencies [Line Items]
Bioreactors used in perfusion cell culture applications | l		2,000
Minimum [Member]
Commitments and Contingencies [Line Items]
Bioreactors used in perfusion cell culture applications | l		50
NGL Impact A [Member] | Research and Development Arrangement [Member]
Commitments and Contingencies [Line Items]
Payments to Navigo in connection with this program, which are recorded to research and development expenses | $			$ 2.4
Before Amendment
Commitments and Contingencies [Line Items]
Lease agreement, space | ft²	76,000
After Amendment
Commitments and Contingencies [Line Items]
Lease agreement, space | ft²	108,000
Fifth Amendment [Member]
Commitments and Contingencies [Line Items]
Rate Per Square Feet	29.00
Increase In Lease Agreement Area	32,000
Increase Per Square Feet	1.00