Long-Term Debt - Loan Agreement (Details)		6 Months Ended	12 Months Ended	17 Months Ended
	Sep. 07, 2016 USD ($) covenant	Mar. 31, 2018	Sep. 30, 2017	Sep. 07, 2019	Jul. 01, 2019 USD ($)	Jun. 30, 2017 USD ($)	Jan. 01, 2017 USD ($)	Dec. 31, 2016 USD ($)
Debt Instrument [Line Items]
Amounts outstanding net of deferred financing costs						$ 4,705,000		$ 8,945,000
Line of Credit [Member] | Loan Agreement [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 15,000,000
Debt instrument term (in years)	3 years
Quarterly decrease in borrowing capacity							$ 250,000
Number of debt covenants (in covenant) | covenant	2
Financial covenant, book value of accounts receivable compared to all borrowings and interest bearing liabilities (percent)	85.00%
Financial covenant, book value of inventory compared to all borrowings and interest bearing liabilities (percent)	55.00%
Financial covenant, book value of plant, property and equipment compared to all borrowings and interest bearing liabilities (percent)	50.00%
Financial covenant, minimum fixed charge coverage ratio	1.20
Amounts outstanding net of deferred financing costs	$ 8,500,000					$ 4,800,000
Weighted average interest rate (percent)						2.97%
Remaining borrowing capacity						$ 9,600,000
Line of Credit [Member] | Loan Agreement [Member] | Daily Floating LIBOR [Member]
Debt Instrument [Line Items]
Interest rate (percent)	2.25%
Line of Credit [Member] | Loan Agreement [Member] | Forecast [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity					$ 12,000,000
Financial covenant, minimum asset coverage ratio		1.15	1.10	1.20