Liquidity (Details) - USD ($)		12 Months Ended
	Jan. 25, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Class of Stock [Line Items]
Cash		$ 2,007,000	$ 3,946,000	$ 1,140,000
Working capital		2,793,000
Net income (loss)		(7,168,000)	5,785,000
Net cash provided by (used in) operating activities		(1,155,000)	1,609,000
Interest payments on indebtedness		318,000	878,000
Outstanding principal, debt obligations		0	1,832,000
Issuance of stock		1,527,000	2,280,000
Principal payments under borrowing arrangements		1,832,000	605,000
Long-term debt		0	$ 1,563,000
Western Alliance Bank Loan Agreement
Class of Stock [Line Items]
Principal payments under borrowing arrangements		$ 800,000
Series C Preferred Stock | Preferred Stock
Class of Stock [Line Items]
Issuance of stock (in shares)	1,750	1,750
Dividend rate, percentage	0.00%
Issuance of stock	$ 1,527,000