Financing Instruments - Loan and Security Agreement (Details)					6 Months Ended	12 Months Ended	17 Months Ended
	Sep. 07, 2016 USD ($) covenant	Apr. 30, 2016 USD ($)	Apr. 21, 2016 USD ($)	Sep. 01, 2010 USD ($)	Mar. 31, 2018	Sep. 30, 2017	Sep. 07, 2019	Jul. 01, 2019 USD ($)	Jan. 01, 2017 USD ($)	Dec. 31, 2016 USD ($)	Sep. 30, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 10, 2013 USD ($)
Line of Credit Facility [Line Items]
Long-term Debt										$ 8,945,000		$ 14,137,000
Repayments of debt		$ 2,000,000
Outstanding balance on loan										9,000,000		14,424,000
Line of Credit [Member] | Loan Agreement [Member]
Line of Credit Facility [Line Items]
Maximum borrowing capacity	$ 15,000,000
Term of debt instrument	3 years
Number of debt covenants | covenant	2
Debt covenant, book value of accounts receivable to all borrowing and interest bearing liabilities, percentage	85.00%
Debt covenant, book value of inventory to all borrowings and interest bearing liabilities, percentage	55.00%
Debt covenant, book value of property, plant and equipment to all borrowings and interest bearing liabilities, percentage	50.00%
Debt instrument, covenant, fixed charge coverage ratio	1.20
Long-term Debt	$ 8,500,000										$ 9,700,000
Long-term debt, weighted average interest rate											2.78%
Cash available under loan											$ 3,200,000
Line of Credit [Member] | Loan Agreement [Member] | London Interbank Offered Rate (LIBOR) [Member]
Line of Credit Facility [Line Items]
Interest rate	2.25%
Line of Credit [Member] | Revolver Loan [Member]
Line of Credit Facility [Line Items]
Maximum borrowing capacity				$ 12,000,000						2,200,000
Repayments of debt	$ 2,700,000
Outstanding balance on loan										$ 6,700,000
Weighted average interest rate										4.60%
Percentage of eligible accounts receivable				85.00%
Percentage of eligible inventory				65.00%
Debt borrowing base, percentage of eligible inventory, raw materials				30.00%
Inventory included in base rate calculation (up to)				$ 6,000,000
Secured Debt [Member]
Line of Credit Facility [Line Items]
Outstanding balance on loan										$ 0		$ 7,688,000
Secured Debt [Member] | Note Purchase Agreement [Member]
Line of Credit Facility [Line Items]
Maximum borrowing capacity													$ 7,200,000.0
Repayments of debt	$ 5,800,000		$ 1,900,000
Weighted average interest rate										25.60%
Scenario, Forecast [Member] | Line of Credit [Member] | Loan Agreement [Member]
Line of Credit Facility [Line Items]
Maximum borrowing capacity								$ 12,000,000
Debt covenant, asset coverage ratio					1.15	1.10	1.20
Subsequent Event [Member] | Line of Credit [Member] | Loan Agreement [Member]
Line of Credit Facility [Line Items]
Line of credit facility borrowing capacity, quarterly decrease in borrowing capacity									$ 250,000