|3 Months Ended|
Mar. 31, 2017
The Company did not issue any warrants during the three months ended March 31, 2017.
For the year 2016, 60,000 common stock purchase warrants were granted to four consultants for services provided. Each warrant was granted with the exercise price of $2.91, which immediately vested, and the expiration date is April 27, 2019.
During 2016, 10,472 warrants expired that were issued in 2011 with exercise prices ranging between $141.00 and $404.50 on a post-reverse split basis.
The Company used the Black-Scholes warrant pricing model to estimate the fair value on the re-measurement dates of the 12,500 warrants that continue to vest during the three months ended March 31, 2017.
The following table summarizes the assumptions used to estimate the fair value of the 12,500 warrants granted during 2015 as of re-measurement dates:
Under the Black-Scholes warrant pricing model, fair value of the 12,500 warrants granted during 2015 is estimated at $3,467 as of re-measurement dates. Compensation expense of $(1,427) and $1,325 was recognized during the three months ended March 31, 2017 and 2016, respectively.
The following table represents warrant activity as of and for the period ended March 31, 2017: