Intangible assets - Schedule of Finite-Lived Intangible Assets (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Schedule of Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	$ 1,230,274	$ 1,088,315
Finite-Lived Intangible Assets, Accumulated Amortization	(218,974)	(134,988)
Intangible assets, net	1,011,300us-gaap_FiniteLivedIntangibleAssetsNet	953,327us-gaap_FiniteLivedIntangibleAssetsNet
Product Certifications
Schedule of Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	475,344	406,706
Finite-Lived Intangible Assets, Accumulated Amortization	(128,732)	(83,405)
Intangible assets, net	346,612	323,301
Patents
Schedule of Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	514,930	441,609
Finite-Lived Intangible Assets, Accumulated Amortization	(62,242)	(39,583)
Intangible assets, net	452,688	402,026
Developed Technology
Schedule of Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	240,000	240,000
Finite-Lived Intangible Assets, Accumulated Amortization	(28,000)	(12,000)
Intangible assets, net	$ 212,000	$ 228,000