Stockholders' Equity (Tables)

9 Months Ended

Sep. 30, 2017

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,				Nine months ended,
Stock-based compensation expense	September 30, 2017		September 30, 2016		September 30, 2017		September 30, 2016
Research and Development	$	0.5	$	0.5	$	1.3	$	2.1
Selling, General and Administrative	$	3.7	$	3.6	$	8.9	$	9.5

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 nine months ended September 30, 2017 follows:

Expected price volatility	78.68% -78.77%
Risk-free interest rate	1.77% -1.87%
Weighted average expected life in years	6 years
Dividend yield	—

Summary of Stock Option Activity

Option activity during the nine months ended September 30, 2017 was as follows:

	Number of Shares			Weighted Average Exercise Price Per Share		Aggregate Intrinsic Value
Outstanding at January 1, 2017		3,468,991		$	4.14
Granted in 2017
Officers and Directors		83,658			2.64
Others		825,003			1.91
Exercised		(151,373	)		2.07
Forfeitures		(1,183,795	)		5.89
Outstanding at September 30, 2017		3,042,484		$	2.92	$	1,466

Summary of Restricted Stock Activity

	Number of Restricted Shares			Weighted Average Fair Market Value Per RSU
Outstanding at January 1, 2017		4,584,297		$	7.29
Granted:
Executive officers		1,640,000			1.80
Directors		162,315			2.80
Employees		540,000			2.04
Vested		(1,568,042	)		2.17
Forfeitures		(554,675	)		2.28
Outstanding at September 30, 2017		4,803,895		$	5.14

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

The weighted average for key assumptions used in determining the fair value of warrants granted during the nine months ended September 30, 2017 follows:

Expected price volatility	78.39%
Risk-free interest rate	1.92%
Weighted average expected life in years	6 years
Dividend yield	—

Summary of Warrant Activity

Warrant activity during the nine months ended September 30, 2017 was as follows:

	Number of Shares		Weighted Average Exercise Price Per Share		Aggregate Intrinsic Value
Outstanding at January 1, 2017		84,986	$	3.53
Granted in 2017		1,701,583		2.38
Exercised		—		—
Forfeitures		—		—
Outstanding at September 30, 2017		1,786,569	$	2.43	$	970