3. Business acquisitions (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013
Business Combinations [Abstract]
Business Acquisition, Cost of Acquired Entity, Purchase Price	$ 4,000,000		$ 4,000,000
Business Combination, Contingent Consideration Arrangements, Change in Range of Outcomes, Contingent Consideration, Liability, Significant Inputs	30%
Business Combination, Contingent Consideration Arrangements, Range of Outcomes, Value, High	0
Business Combination, Contingent Consideration Arrangements, Range of Outcomes, Value, Low	200,000
Business Acquisition, Contingent Consideration, at Fair Value, Noncurrent	824,000	60,000
Business Acquisition, Contingent Consideration, at Fair Value	960,000
Business Combination, Contingent Consideration Arrangements, Change in Amount of Contingent Consideration, Liability	900,000
Short-Duration Contracts, Discounted Liabilities, Discount Rate, Low End of Range	4.00%
Short-Duration Contracts, Discounted Liabilities, Discount Rate, High End of Range	5.00%
Business Combination, Contingent Consideration Arrangements, Change in Range of Outcomes, Contingent Consideration, Liability, Value, Low	300,000
Business Combination, Contingent Consideration Arrangements, Change in Range of Outcomes, Contingent Consideration, Liability, Value, High	1,200,000
Business Combination, Goodwill Recognized, Description	$1,152,000
Business Acquisition, Transaction Costs	159,000
Business Combination, Integration Related Costs	78,000
Sales Revenue, Goods, Net	1,892,000
Other Income	23,000
Amortization of Intangible Assets		139,000
Business Combination, Acquisition Related Costs		$ 78,000