Stockholders' Equity (Tables)

9 Months Ended

Sep. 30, 2018

Federal Home Loan Banks [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, 2018		September 30, 2017		September 30, 2018		September 30, 2017
Research and Development	$	0.02	$	0.5	$	1.1	$	1.3
Selling, General and Administrative	$	0.9	$	3.7	$	3.8	$	8.9

Key Assumptions Used in Determining Fair Value of Options Granted

The key assumptions used in determining the fair value of options granted during the nine months ended September 30, 2018 follows:

Expected price volatility	60.34%-68.77%
Risk-free interest rate	2.05%-2.82%
Weighted average expected life in years	6 years
Dividend yield	—

Summary of Stock Option Activity

Option activity during the nine months ended September 30, 2018 was as follows:

	Number of shares			Weighted average exercise price per share		Aggregate intrinsic value
Outstanding at January 1, 2018		2,712,954		$	2.98	$	1,190
Granted in 2018:
Officers and Directors		1,160,341			2.41
Employees		1,099,870			2.50
Exercised		(285,403	)		1.99
Forfeitures		(375,785	)		3.57
Outstanding at September 30, 2018		4,311,977		$	3.17	$	1,405

Summary of Restricted Stock Activity

Restricted stock activity during the nine months ended September 30, 2018 was as follows:

	Number of restricted shares			Weighted average fair market value per RSU
Outstanding at January 1, 2018		4,706,895		$	5.20
Granted:
Executive officers		1,038,434			2.23
Directors		469,261			2.59
Employees		317,177			2.10
Vested		(1,733,731	)		2.50
Forfeitures		(442,009	)		2.63
Conversions		(2,119,925	)		2.72
Outstanding at September 30, 2018		2,236,102		$	5.15