Summary of Significant Accounting Policies - Accounts Receivable (Details) - USD ($)	Dec. 31, 2023	Dec. 31, 2022
Accounts receivable
Trade accounts receivable	$ 11,489,000	$ 10,498,000
Unbilled accounts receivable	475,000	551,000
Allowance for product returns and price adjustments	(410,000)	(384,000)
Accounts receivable, net	$ 11,554,000	$ 10,665,000