Condensed Consolidated Balance Sheets (Parenthetical) - USD ($)	Mar. 31, 2024	Dec. 31, 2023
Allowance for doubtful accounts	$ 1,060,000	$ 1,113,000
Accumulated depreciation, Property, plant and equipment	29,427,000	28,920,000
Accumulated depreciation, Rental assets	7,859,000	7,003,000
Accumulated amortization, Intangible assets	$ 42,770,000	$ 39,987,000
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized (in shares)	2,000,000	2,000,000
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	150,000,000	150,000,000
Common stock, shares issued (in shares)	11,882,844	11,878,557
Common stock, shares outstanding (in shares)	11,882,844	11,878,557
Series E preferred stock
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized (in shares)	39,500	39,500
Preferred stock issued (in shares)	25,000	25,000
Preferred stock, shares outstanding (in shares)	25,000	25,000
Preferred stock, liquidation preference	$ 35,913,326	$ 35,913,326