Leases - Additional Information (Details) $ in Thousands	1 Months Ended			3 Months Ended
	Nov. 30, 2016 ft² renewal_term	Oct. 31, 2014 renewal_term	May 31, 2013 ft² renewal_term	Sep. 30, 2019 USD ($)	Jul. 01, 2019 USD ($)	Jun. 01, 2018 ft²	Feb. 28, 2015 ft²
Leases [Line Items]
Incremental borrowing rate				11.00%
Cash payments | $				$ 96
Weighted-average remaining lease term for operating leases				5 years 1 month 6 days
1st Detect
Leases [Line Items]
Lease, expiration date		Apr. 30, 2020
Lessee, Operating Lease, Existence of Option to Extend [true false]		true
Number of renewal terms | renewal_term		2
Renewal term		5 years
Leased premises, right of first refusal exercised							9,138
Austin, Texas
Leases [Line Items]
Leased premises	5,219
Lease, expiration date	Dec. 31, 2023
Lessee, Operating Lease, Existence of Option to Extend [true false]	true
Number of renewal terms | renewal_term	1
Renewal term	5 years
Period before expiration of lease that renewal contract must be signed	8 months
Webster, Texas
Leases [Line Items]
Original lease area of land removed						8,118
Leased premises remaining area						17,560
Webster, Texas | 1st Detect | Research and Development and Production Facility
Leases [Line Items]
Leased premises			16,540
Lease, expiration date			Jun. 30, 2018
Lessee, Operating Lease, Existence of Option to Extend [true false]			true
Number of renewal terms | renewal_term			2
Renewal term			5 years
Lease term			62 months
ASU 2016-02
Leases [Line Items]
Cumulative impact of change in accounting policy | $					$ 230