(Details) - USD ($)	3 Months Ended	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2019	Jun. 30, 2018	Mar. 31, 2019	Dec. 31, 2018
Loss Contingencies [Line Items]
Expected insurance proceeds	$ 973,000	$ 973,000
Accrued remediation contingency (Note 14)	2,228,000	2,228,000		$ 1,223,000	$ 0
Insurance deductible		250,000
Addition to claims receivable	1,005,000	1,005,000
Addition to accrued liability	1,005,000
Receivable from insurance carrier	1,978,000	1,978,000			0
Non-conformance accrual	2,228,000	2,228,000
Accounts receivable	14,627,000	14,627,000			$ 18,399,000
Change in warranty liability balance		0	$ 0
Warranty liability balance	159,000	159,000	$ 159,000
Customer One
Loss Contingencies [Line Items]
Accounts receivable	$ 500,000	$ 500,000