Leases - Additional Information (Detail) $ in Thousands	Mar. 31, 2019 USD ($)	Jan. 31, 2019 USD ($) ft²
Leases [Line Items]
Total right-of-use assets	$ 1,493
Total lease liabilities	$ 1,635
Test & Measurement Product Line [Member]
Leases [Line Items]
Operating lease term of contract		11 years
Area of lease \| ft²		21,030
Operating lease not yet commenced, amount		$ 5,400

Term of lessee's operating lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (a)(3)
-URI http://asc.fasb.org/extlink&oid=77888426&loc=SL77918673-209980

Name:	us-gaap_LesseeOperatingLeaseTermOfContract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	instant