Commitments and Contingencies - Schedule of Future Minimum Payments Under Operating and Capital Leases (Detail) $ in Thousands	Dec. 31, 2017 USD ($)
Commitments And Contingencies Disclosure [Abstract]
Operating leases, 2018	$ 1,979
Operating leases 2019	823
Operating leases, 2020	613
Operating leases, 2021	259
Operating leases, 2022	0
Operating leases, Thereafter	0
Operating leases, Total minimum payments	3,674
Capital leases, 2018	546
Capital leases, 2019	498
Capital leases, 2020	160
Capital leases, 2021	0
Capital leases, 2022	0
Capital leases, Thereafter	0
Capital leases, Total minimum payments	1,204
Less: amount representing interest	128
Present value of capital lease obligations	1,076
Less: current portion	463
Capital lease obligation, net of current portion	$ 613

Amount equal to the present value (the principal) at the beginning of the lease term of minimum lease payments during the lease term (excluding that portion of the payments representing executory costs such as insurance, maintenance, and taxes to be paid by the lessor, together with any profit thereon) net of payments or other amounts applied to the principal through the balance sheet date.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=84164817&loc=d3e45280-112737

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(16))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910