Quarterly report pursuant to Section 13 or 15(d)

Fair Value Measurements (Tables)

Fair Value Measurements (Tables)
6 Months Ended
Jun. 30, 2015
Fair Value Disclosures [Abstract]  
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block]
The following table presents the activity for those items measured at fair value on a recurring basis using Level 3 inputs for the six months ended June 30, 2014:
Instruments - Stock
Purchase Warrants
Balance at December 31, 2013
Change in fair value
Exercise of underlying warrants
Balance at June 30, 2014