Equity Compensation Plans (Tables)

9 Months Ended

Sep. 30, 2019

Share-based Payment Arrangement [Abstract]

Schedule of Compensation Cost for Share-based Payment Arrangements, Allocation of Share-based Compensation Costs by Plan

The following table sets forth the components of the Company’s share-based compensation expense for the three and nine month periods ended September 30, 2019 and 2018 (in thousands):

	Three Months Ended September 30,				Nine Months Ended September 30,
	2019		2018		2019		2018
Stock options	$	1,453	$	2,357	$	4,274	$	7,993
Employee stock purchase plan	339		—		837		—
Restricted stock units and Performance share units	3,934		3,389		10,923		9,206
Total stock-based compensation expense	$	5,726	$	5,746	$	16,034	$	17,199

Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions

Set forth in the following table are the weighted-average assumptions used in estimating the grant date fair value of the stock options granted under the Company's equity compensation plans during the three and nine month periods ended September 30, 2019, along with the weighted-average grant date fair values:

	Three Months Ended September 30,						Nine Months Ended September 30,
	2019			2018			2019			2018
Expected volatility	55.86		%	—		%	56.45		%	—		%
Expected life (in years)	6.2			—			6.2			0
Risk-free interest rate	1.60		%	—		%	2.34		%	—		%
Dividend yield	—			—			—			—
Fair value per stock option	$	1.73		$	—		$	2.35		$	—
Forfeiture rate	8		%	—		%	8		%	—		%

Schedule of Share-based Compensation, Activity

The table below sets forth a summary of stock option activity within the Company’s stock-based compensation plans for the nine month period ended September 30, 2019:

	Number of Options (in thousands)		Weighted Average Exercise Price		Weighted Average Remaining Contractual Term (Years)	Aggregate Intrinsic Value (in thousands) (1)
Outstanding at December 31, 2018	3,418		$	28.55	3.69	$	—
Granted	3,088		4.27
Exercised	—		—
Forfeited	(1,333	)	26.22
Outstanding at September 30, 2019	5,173		$	14.66	7.05	$	120
Exercisable at September 30, 2019	1,713		$	30.48	3.42	$	—

(1) The Aggregate Intrinsic Value of stock options outstanding and exercisable is defined as the difference between the market value of the Company’s common stock as of the date indicated and the exercise price of the stock options. Stock options for which the exercise price exceeded the market price have been omitted. Fluctuations in the intrinsic value of both outstanding and exercisable options may result from changes in underlying stock price and the timing and volume of option grants, exercises and forfeitures.

Schedule of Nonvested Restricted Stock Units Activity

Set forth below is a summary of unvested RSU activity during the nine month period ended September 30, 2019:

	Number of Units (in thousands)	Weighted Average Per Share Grant Date Fair Value
Unvested at December 31, 2018	1,643	$	19.85
Granted	4,296	$	4.11
Vested	(631)	$	24.10
Forfeited	(295)	$	14.97
Unvested at September 30, 2019	5,013	$	7.21

Schedule of Nonvested Performance-based Units Activity

Set forth below is a summary of unvested PSU activity during the nine month period ended September 30, 2019:

	Total Number of Units (in thousands)		Weighted Average Grant Date Fair Value per Unit		Vesting Based on Performance Conditions		Weighted Average Grant Date Fair Value per Unit		Vesting Based on Market Conditions	Weighted Average Grant Date Fair Value per Unit
Unvested at December 31, 2018	—		$	—	—		$	—	—	$	—
Granted	1,239		3.99		985		4.06		254	3.73
Vested	—		—		—		—		—	—
Forfeited	(21	)	4.06		(21	)	4.06		—	—
Unvested at September 30, 2019	1,218		$	3.99	964		$	4.06	254	$	3.73

Schedule of Share-based Payment Award, Performance Stock Units, Valuation Assumptions

Set forth below is a summary of the valuation inputs for PSUs granted with vesting subject to market conditions during the nine month period ended September 30, 2019:

Valuation Inputs for PSUs with Vesting Subject to Market Conditions:
PSUs Issued (units in thousands)	254
Risk Free Rate	2.58		%
Volatility	55.10		%
Dividend	—		%
Valuation Per Share	$	3.73
Total Fair Value (in thousands)	$	947
Expected Term (years)	4
Forfeiture Rate Assumed	8.00		%