Leases - Schedule of Lease Expense, Cash Flow, Operating and Finance Lease Assets and Liabilities, Average Lease Term and Average Discount Rate (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Finance lease expense:
Amortization of right-of-use assets	$ 335	$ 615	$ 1,006	$ 906
Interest on lease liabilities	20	43	65	63
Operating lease expense	727	1,699	2,375	2,534
Total lease expense	1,082	2,357	3,446	3,503
Cash paid for amounts included in the measurement of lease liabilities
Operating cash outflows from finance leases	20	43	65	63
Operating cash outflows from operating leases	884	1,818	2,687	2,692
Financing cash outflows from finance leases	367	467	1,012	723
Right-of-use assets obtained in exchange for finance lease liabilities, net of terminations and disposals	50	180	885	252
Right-of-use assets obtained in exchange for operating lease liabilities, net of terminations and disposals	76	$ 422	284	$ 637
Operating leases:
Other non-current assets	11,442		11,442		$ 13,598
Accrued liabilities	$ (2,473)		$ (2,473)		$ (2,868)
Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	us-gaap:AccountsPayableAndAccruedLiabilitiesCurrent		us-gaap:AccountsPayableAndAccruedLiabilitiesCurrent		us-gaap:AccountsPayableAndAccruedLiabilitiesCurrent
Other non-current liabilities	$ (9,509)		$ (9,509)		$ (11,513)
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	Other non-current liabilities		Other non-current liabilities		Other non-current liabilities
Total operating lease liabilities	$ (11,982)		$ (11,982)		$ (14,381)
Operating Lease, Liability, Statement of Financial Position [Extensible Enumeration]	us-gaap:AccountsPayableAndAccruedLiabilitiesCurrentAndNoncurrent		us-gaap:AccountsPayableAndAccruedLiabilitiesCurrentAndNoncurrent		us-gaap:AccountsPayableAndAccruedLiabilitiesCurrentAndNoncurrent
Property, plant and equipment gross	$ 6,937		$ 6,937		$ 5,735
Accumulated depreciation	(4,325)		(4,325)		(3,319)
Property, plant and equipment, net	2,612		2,612		2,416
Current portion of long-term debt	(1,075)		(1,075)		(1,113)
Long-term debt (less current portion)	(1,865)		(1,865)		(2,275)
Total finance lease liabilities	$ (2,940)		$ (2,940)		$ (3,388)
Weighted-average remaining lease term - finance leases (years)	3 years 6 months		3 years 6 months		3 years 10 months 24 days
Weighted-average remaining lease term - operating leases (years)	5 years 2 months 12 days		5 years 2 months 12 days		6 years 1 month 6 days
Weighted-average discount rate - finance leases	2.80%		2.80%		3.00%
Weighted-average discount rate - operating leases	3.60%		3.60%		3.80%