Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
ASSETS
Cash and cash equivalents	$ 1,102	$ 5,476
Treasury bills	5,248	0
Available-for-sale securities	3,677	3,181
Trade receivables, less allowance for doubtful accounts of $10 and $9, respectively	602	731
Inventories	1,330	1,228
Income tax receivable	0	17
Other current assets	75	116
Total current assets	12,034	10,749
Property and equipment, net	1,304	1,179
Total assets	13,338	11,928
LIABILITIES AND STOCKHOLDERS' EQUITY
Accounts payable	94	110
Accrued expenses	227	214
Income tax payable	313	0
Total current liabilities	634	324
Deferred income tax liability	1,455	1,225
Commitments and contingencies
Stockholders' equity
Common stock par value $0.10 per share; authorized 10,000,000 shares; issued and outstanding: 3,391,912 and 3,389,577 shares, respectively	339	339
Additional paid-in capital	1,575	1,561
Retained earnings	7,113	6,570
Accumulated other comprehensive income (unrealized gain on available-for-sale securities, net of income tax)	2,222	1,909
Total stockholders' equity	11,249	10,379
Total liabilities and stockholders' equity	$ 13,338	$ 11,928