Employee Stock and Benefit Plans (Tables)

12 Months Ended

Dec. 31, 2018

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Schedule of Total Stock-based Compensation Expense

Stock-based compensation expense recognized in our consolidated statements of operations includes amounts related to stock options, restricted stock, and employee stock purchase plans and was as follows (in thousands):

	Years Ended December 31,
	2018		2017		2016
Total stock-based compensation expense	$	2,508	$	3,675	$	5,424

Weighted-Average Assumptions Used to Determine Fair Value of Options Granted

The fair value of options granted, excluding the options related to the 2016 Exchange described below, used the following weighted average assumptions:

	Years ended December 31,
	2018		2017		2016
Expected dividend yield	—	%	—	%	—	%

Risk-free interest rate	2.71	%	1.99	%	1.59	%
Expected term (years)	4.3		5.3		5.1
Volatility	35	%	36	%	35	%

Schedule of Nonvested Restricted Stock Units Activity

Restricted stock unit and award activity was as follows (shares are in thousands):

	Number of Shares		Weighted Average Grant Date Fair Value Per Share		Total Grant Date Fair Value of Vested Awards (000's)
Nonvested shares, December 31, 2015	324		$	5.94
Granted	832		3.75
Vested	(802	)	3.83		$	3,069
Forfeited/Canceled	(22	)	5.61
Nonvested shares, December 31, 2016	332		$	5.59
Granted	230		4.66
Vested	(347	)	5.64		$	1,957
Forfeited/Canceled	(23	)	4.38
Nonvested shares, December 31, 2017	192		$	4.53
Granted	943		2.56
Vested	(402	)	3.18		$	1,278
Forfeited/Canceled	(35	)	4.69
Nonvested shares, December 31, 2018	698		$	2.63

Schedule of Stock Options and Restricted Stock Units Activity

Stock option activity (shares are in thousands):

	Options Outstanding				Weighted Average Grant Date Fair Value
	Number of Shares		Weighted Average Exercise Price
Outstanding, December 31, 2015	5,517		$	7.58
Options granted at common stock price	1,230		4.50		$	1.51
Options cancelled as part of stock option exchange	(1,961	)	8.11
Options granted as part of stock option exchange	1,961		4.73		$	0.74
Options exercised	(90	)	3.69
Options cancelled	(796	)	8.81
Outstanding, December 31, 2016	5,861		$	5.73
Options granted at common stock price	993		4.29		$	1.51
Options exercised	(21	)	3.51
Options cancelled	(757	)	6.00
Outstanding, December 31, 2017	6,076		$	5.47
Options granted at common stock price	2,339		3.17		$	1.01
Options exercised	—		—
Options cancelled	(1,087	)	6.68
Outstanding, December 31, 2018	7,328		$	4.56
Exercisable, December 31, 2018	4,078		$	5.35
Vested and expected to vest, December 31, 2018	6,260		$	4.73