Equity Incentive Plans (Tables)

12 Months Ended

Dec. 31, 2015

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Share-Based Compensation Expense from All Stock Options Granted Charged to Consolidated Statements of Operations

The share-based compensation expense from all stock options granted that has been charged to our consolidated statements of operations and comprehensive loss in those periods was as follows (in thousands):

	Years ended December 31,
	2015		2014
Selling, general and administrative expense	$	2,077	$	1,607
Research and development expense		598		425
Share-based compensation expense	$	2,675	$	2,032

Summary of Option Activity

The following table summarizes our stock option activity for the year ended December 31, 2015:

	Shares Underlying Option Awards			Weighted-Average Exercise Price		Weighted-Average Remaining Contractual Years		Aggregate Intrinsic Value
								(in thousands)
Outstanding at January 1, 2015		13,616,137		$	1.00
Granted		13,114,372		$	0.55
Exercised		-		$	—
Expired/cancelled/forfeited		(3,827,782	)	$	0.65
Outstanding at December 31, 2015		22,902,727		$	0.80		7.46	$	4
Options exercisable at December 31, 2015		10,428,421		$	1.10		5.72	$	-
Vested and expected to vest at December 31, 2015		21,897,047		$	0.81		7.38	$	3

Black-Scholes Option-Valuation Model and the Calculation of Share-based Compensation for Option Grants to Employees and Non-Employee Directors

The assumptions used in the Black-Scholes option-valuation model and the calculation of share-based compensation for option grants to employees and non-employee directors during the years ended December 31, 2015 and 2014 are as follows:

	Years ended December 31,
	2015			2014
Risk-free interest rate	1.6 - 1.9%			1.9 - 2.1%
Dividend yield	0.0%			0.0%
Expected volatility	78 - 99%			104 - 112%
Expected term (in years)	5.3 - 6.2 years			5.4 - 6.2 years
Forfeiture rate		7	%	9%