Leases - Components of Net Investment in Sales-Type Leases (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Sales Type Leases Net Investment In Leases [Abstract]
Current minimum lease payments receivable	$ 1,201	$ 11,339
Non-current minimum lease payments receivable	889	1,670
Total minimum lease payments receivable	2,090	13,009
Less: Current unearned revenue	365	631
Less: Non-current unearned revenue	163	473
Net investment in sales-type leases	$ 1,562	$ 11,905

Present value of lease payments not yet received by lessor and amount expected to be derived from underlying asset, following end of lease term guaranteed by lessee or other third party unrelated to lessor, from sales-type lease.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 30
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=119202524&loc=SL77919379-209981

Name:	us-gaap_SalesTypeLeaseLeaseReceivable
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant