Significant Market Segments And Customers (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Significant market segments
Accounts receivable	$ 5,913	$ 4,171
Sales | International sales | Non-US
Significant market segments
Direct sales percentage of sales	10.00%	9.00%
Sales | DaVita | Customer concentration
Significant market segments
Direct sales percentage of sales	47.00%	50.00%
Sales | Baxter | Customer concentration
Significant market segments
Direct sales percentage of sales	26.00%	25.00%
Sales | Nipro Medical Corporation | International sales | Non-US
Significant market segments
Direct sales percentage of sales	8.00%	7.00%
Accounts receivable | DaVita
Significant market segments
Accounts receivable	$ 1,000	$ 1,100
Accounts receivable | Baxter
Significant market segments
Accounts receivable	$ 3,500	$ 1,600