Financial instruments (Tables)

12 Months Ended

Dec. 31, 2016

Investments, All Other Investments [Abstract]

Fair Value Measurements, Recurring and Nonrecurring [Table Text Block]

The following table presents the Company’s fair value hierarchy for assets and liabilities measured at fair value as of December 31, 2016 and 2015:

	December 31, 2016
	Level 1		Level 2		Level 3		Total
Liabilities:
Recurring
Net liability arising from put/call options	$	-	$	-	$	680,000	$	680,000

	December 31, 2015
	Level 1		Level 2		Level 3		Total
Assets:
Recurring
Restricted cash	$	428,203	$	-	$	-	$	428,203
Certificate of deposit		-		5,637,538		-		5,637,538
Total recurring	$	428,203	$	5,637,538	$	-	$	6,065,741

Fair Value Measurements, Nonrecurring [Table Text Block]

The activity for the Level 3 liability for the year ended December 31, 2016:

Net liability arising from put/call options(1)
Balance as of December 31, 2015	$	-
Issuance		383,000
Unrealized loss		297,000
Balance as of December 31, 2016	$	680,000

(1) The net liability arising from the put/call options is included other liabilities in the accompanying consolidated balance sheets as of December 31, 2016.