Contingencies (Details) - USD ($)	3 Months Ended		9 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Loss Contingencies [Line Items]
Expected insurance proceeds		$ 973,000
Accrued remediation contingency		1,223,000	$ 760,000		$ 0
Insurance deductible		$ 250,000
Addition to claims receivable	$ 1,005,000
Addition to accrued liability	$ 1,005,000
Receivable from insurance carrier			1,991,000		0
Non-conformance accrual			760,000
Accounts receivable			10,124,000		$ 18,399,000
Change in warranty liability balance			0	$ 0
Warranty liability balance			159,000	$ 159,000
Customer One
Loss Contingencies [Line Items]
Accounts receivable			$ 500,000