2. Summary of significant accounting policies (Details) (USD $)	12 Months Ended				24 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2013
Accounting Policies [Abstract]
Allowance for Doubtful Accounts Receivable, Current		$ 66,000	$ 63,000
Depreciation		1,183,000	1,339,000	1,216,000
Product Warranty Accrual, Noncurrent		101,000	84,000
Research and Development Expense	4,065,000	4,239,000	3,418,000	4,065,000
Capitalized Computer Software, Net		528,000	370,000
Capitalized Computer Software, Amortization	199,000	189,000	62,000		20,132,012
Finite-Lived Intangible Asset, Useful Life			2 years
Advertising Expense		$ 949,000	$ 871,000	$ 1,058,000