Stockholders' Equity (Tables)

3 Months Ended

Mar. 31, 2016

Equity [Abstract]

Summary of Allocated Stock-based Compensation Expense

The Company’s stock-based compensation expense is allocated between research and development and selling, general and administrative as follows:

	Three months ended,
Stock-based compensation expense	March 31, 2016	March 31,   2015
Research and Development	$   1,128	$   852
Selling, General and Administrative	$  2,983	$ 2,655

Weighted Average for Key Assumptions Used in Determining Fair Value of Options Granted

The weighted average for key assumptions used in determining the fair value of options granted during the three months ended March 31, 2016 follows:

Expected price volatility	72.15% -82.71%
Risk-free interest rate	1.22% - 1.70%
Weighted average expected life in years	6 years
Dividend yield	—

Summary of Stock Option Activity

Option activity during the three months ended March 31, 2016 was as follows:

	Number of      Shares			Weighted Average Exercise Price   Per Share		Aggregate    Intrinsic Value
Outstanding at January 1, 2016		3,397,529		$	5.42
Granted		190,513			4.42
Exercised		(112,425	)		2.00
Forfeitures		(36,814	)		11.98
Outstanding at March 31, 2016		3,438,803		$	5.42	$	874

Summary of Restricted Stock Activity

Restricted stock activity during the three months ended March 31, 2016 was as follows:

	Number of Restricted Shares		Weighted Average Fair Market Value Per RSU
Outstanding at January 1, 2016		4,298,154	$	10.23
Granted:
Executive officers		913,000		3.80
Directors		—		—
Employees		30,000		3.60
Vested		(104,025)		3.89
Forfeitures		(555,791)		12.56
Outstanding at March 31, 2016		4,581,338	$	8.34