Share-Based Compensation (Tables)

3 Months Ended

Mar. 31, 2016

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Weighted Average Fair Value of Employee Stock Options Granted

During the three months ended March 31, 2016 and 2015, the per share weighted average fair value of employee stock options granted were as follows:

	Three Months Ended
	March 31,
	2016		2015
Stock Options	$	0.44	$	1.29
Restricted Stock Units		—		—
Stock Purchase Rights		0.41		0.67

Estimated Grant Date Fair Values of Stock Options with Weighted Average Assumptions

The estimated grant date fair values of the stock options and stock purchase rights were calculated using the Black-Scholes valuation model, and the following weighted average assumptions:

	Three Months Ended
	March 31,
	2016		2015
Stock Option Plans
Weighted-average expected term	5.0 Years		5.0 Years
Expected volatility		80%		85%
Risk-free interest rate		1.52%		1.40%
Dividend yield		0%		0%
Employee Stock Purchase Plan
Weighted-average expected term	0.6 Years		0.5 Years
Expected volatility		75%		60%
Risk-free interest rate		0.33%		1.62%
Dividend yield		0%		0%