Summary of significant accounting policies (Details Textual) - USD ($)	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015	May. 08, 2015
Significant Accounting Policies [Line Items]
Allowance for Doubtful Accounts Receivable	$ 13,352		$ 15,596
Inventory Valuation Reserves	$ 614,109		599,064
Operating Loss Carryforwards			90,297,000
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	5,900,000	8,900,000
FDIC limit of insurable cash	$ 250,000
Goodwill	600,814		637,528
Letters of Credit Outstanding, Amount	243,380		$ 243,380
Amortization of Intangible Assets	66,954
Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months	$ 268,000
Developed Technology Rights [Member]
Significant Accounting Policies [Line Items]
Finite-Lived Intangible Asset, Useful Life	7 years
Customer Relationships [Member]
Significant Accounting Policies [Line Items]
Finite-Lived Intangible Asset, Useful Life	7 years
Trademarks [Member]
Significant Accounting Policies [Line Items]
Finite-Lived Intangible Asset, Useful Life	10 years
Common Stock [Member]
Significant Accounting Policies [Line Items]
Convertible Preferred Stock, Shares Issued upon Conversion				7,374,852
Series A Convertible Redeemable Preferred Stock
Significant Accounting Policies [Line Items]
Temporary Equity Redemption Request Of Minimum Percentage Of Holders Of Outstanding Preferred Stock Required	70.00%
Temporary Equity, Shares Outstanding		3,999,864
Accounts Receivable | Customer One
Significant Accounting Policies [Line Items]
Concentration Risk, Percentage	10.00%
Sales Revenue, Net [Member] | Hitachi High - Technologies Corporation
Significant Accounting Policies [Line Items]
Concentration Risk, Percentage	10.00%	54.00%
Maximum
Significant Accounting Policies [Line Items]
Accounts Receivable Period Due	60 days
Minimum
Significant Accounting Policies [Line Items]
Accounts Receivable Period Due	30 days