Leases - Additional Information (Detail) $ in Thousands	1 Months Ended					12 Months Ended
	Nov. 30, 2020 USD ($)	May 31, 2019 USD ($)	Nov. 30, 2018 USD ($) ft²	May 31, 2016 USD ($)	Mar. 31, 2015	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Other Commitments [Line Items]
Tenant improvement allowance received						$ 11,400	$ 5,000
Property and equipment, net						131,547	56,467
Operating lease right-of-use assets						60,904	$ 63,815
Lease liabilities						$ 86,681
Rockville, Maryland [Member]
Other Commitments [Line Items]
Operating lease expiration year						2028
9804 Medical Center Drive [Member]
Other Commitments [Line Items]
Tenant improvement allowance received						$ 19,500
Tenant improvement allowance receivable						1,500
Property and equipment, net						113,200
Operating lease right-of-use assets						48,300
Lease liabilities						72,500
9804 Medical Center Drive [Member] | Building [Member]
Other Commitments [Line Items]
Property and equipment, net						41,200
9804 Medical Center Drive [Member] | Manufacturing Facility [Member]
Other Commitments [Line Items]
Property and equipment, net						$ 72,000
9804 Medical Center Drive [Member] | Rockville, Maryland [Member]
Other Commitments [Line Items]
Number of square feet to be constructed | ft²			186,000
Construction completion, description						The initial construction of the building was performed by the landlord and the lease commenced in September 2020 upon delivery of the leased premises to the Company to make additional improvements to the building.
Lease commenced date			2020-09
Lease expiration date			Sep. 30, 2036
Lease not yet commenced, option to terminate the lease						true
Lease not yet commenced, option to terminate the lease, description						The Company has the option to extend the term of the lease for up to 10 additional years and the option to terminate the lease, with payment of an early termination fee, after 12 years from the delivery of the leased premises to the Company.
Lease not yet commenced, additional lease term			10 years
Minimum release term for option to terminate			12 years
Letters of credit			$ 1,100
9712 Medical Center Drive [Member] | Rockville, Maryland [Member]
Other Commitments [Line Items]
Lease commenced date					2015-04
Lease expiration date						Sep. 30, 2036
Tenant improvement allowance received						$ 400
Lease term						In October 2020, the 9712 Medical Center Drive Lease was amended to extend the lease term from September 2021 to February 2027, subject to extension options held by the Company.
Operating lease, existence of option to extend the lease						true
Increase decrease in right-of-use assets and lease liabilities						$ 7,200
Operating lease, option to extend description						The Company has an option to extend the term of the lease for three additional years, as well as an option to extend the lease term to be coterminous with the 9804 Medical Center Drive Lease, which expires in September 2036.
Additional lease term under option to extend						3 years
400 Madison Avenue [Member] | 400 Madison Lease [Member]
Other Commitments [Line Items]
Letters of credit				$ 200
Increase decrease in right-of-use assets and lease liabilities		$ 5,200
Operating Lease Commencement Year				2016-07
Tenant improvement allowance entitled to received				$ 700
9600 Blackwell Road [Member] | Rockville, Maryland [Member]
Other Commitments [Line Items]
Lease expiration date	Sep. 30, 2021
Increase decrease in right-of-use assets and lease liabilities	$ (700)
Operating lease, existence of option to terminate	true
Early termination fee	$ 400