|3 Months Ended|
Mar. 31, 2018
|Stock Plans [Abstract]|
|Stock Plans [Text Block]||
The following table summarizes the stock-based compensation expense recorded for awards under the stock option plans for the three month periods ended March 31, 2018 and 2017:
No tax benefit was recognized related to stock-based compensation expense since we have incurred operating losses and we have established a full valuation allowance to offset all the potential tax benefits associated with our deferred tax assets.
We use the Black-Scholes-Merton option-pricing model with the following assumptions to estimate the stock-based compensation expense for the three month period ended March 31, 2018 and 2017:
Options to purchase approximately 945,000 and approximately 436,000 common shares were granted during the three month periods ended March 31, 2018 and 2017, respectively.
The following table summarizes option activity for the three month period ended March 31, 2018:
No shares of restricted stock were awarded to employees, directors and consultants during the three month periods ended March 31, 2018 and 2017.
As of March 31, 2018, there was approximately $892,000 of total unrecognized compensation expense related to non-vested stock options. This expense is expected to be recognized over a weighted-average period of approximately 0.9 years.
The entire disclosure for compensation-related costs for equity-based compensation, which may include disclosure of policies, compensation plan details, allocation of equity compensation, incentive distributions, equity-based arrangements to obtain goods and services, deferred compensation arrangements, employee stock ownership plan details and employee stock purchase plan details.
Reference 1: http://www.xbrl.org/2003/role/presentationRef