Equity Incentive Plans and Stock-Based Compensation (Tables)

6 Months Ended

Jun. 30, 2020

Share-based Payment Arrangement [Abstract]

Schedule of shares available for grant

A summary of shares available for grant under the Company’s plans is as follows:

	Shares Available  for Grant
Shares available as of December 31, 2019	6,826,863
Increase in shares approved for issuance (3)	7,800,000
Stock options granted	—
Stock options forfeited	57,836
Nonvested equity stock and stock units granted (1) (2)	(3,358,046)
Nonvested equity stock and stock units forfeited (1)	803,481
Total available for grant as of June 30, 2020	12,130,134

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(1)For purposes of determining the number of shares available for grant under the 2015 Equity Incentive Plan (the “2015 Plan”) against the maximum number of shares authorized, each share of restricted stock granted reduces the number of shares available for grant by 1.5 shares and each share of restricted stock forfeited increases shares available for grant by 1.5 shares.

(2)Amount includes approximately 0.5 million shares that have been reserved for potential future issuance related to certain performance unit awards granted in the first quarter of 2020 and discussed under the section titled “Nonvested Equity Stock and Stock Units” below.

(3)On April 30, 2020, the Company’s stockholders approved an additional 7,800,000 shares for issuance under the 2015 Plan.

^[1]

Schedule of stock option activity

The following table summarizes stock option activity under the 2015 Plan for the six months ended June 30, 2020 and information regarding stock options outstanding, exercisable, and vested and expected to vest as of June 30, 2020.

	Options Outstanding
(In thousands, except per share amounts and years)	Number of  Shares	Weighted  Average  Exercise Price  Per Share		Weighted  Average  Remaining  Contractual  Term (years)	Aggregate  Intrinsic  Value
Outstanding as of December 31, 2019	1,639,146	$	11.37
Options granted	—	$	—
Options exercised	(473,170)	$	10.48
Options forfeited	(57,836)	$	18.73
Outstanding as of June 30, 2020	1,108,140	$	11.36	4.86	$	4,495
Vested or expected to vest at June 30, 2020	1,105,704	$	11.36	4.85	$	4,490
Options exercisable at June 30, 2020	889,527	$	10.98	4.08	$	3,996

Weighted-average assumptions for employee stock purchase plan

	Employee Stock Purchase Plan
	Six Months Ended
	June 30,
	2020			2019
Employee Stock Purchase Plan:
Expected stock price volatility	46		%	32		%
Risk free interest rate	0.12		%	2.44		%
Expected term (in years)	0.5			0.5
Weighted-average fair value of purchase rights granted under the purchase plan	$	3.50		$	2.80

Schedule of nonvested equity stock and stock units activity

The following table reflects the activity related to nonvested equity stock and stock units for the six months ended June 30, 2020:

Nonvested Equity Stock and Stock Units	Shares	Weighted-  Average  Grant-Date  Fair Value
Nonvested at December 31, 2019	5,289,483	$	11.27
Granted	1,872,547	$	15.65
Vested	(1,330,009)	$	11.38
Forfeited	(431,636)	$	11.50
Nonvested at June 30, 2020	5,400,385	$	12.75

[1] Amount includes approximately 0.5 million shares that have been reserved for potential future issuance related to certain performance unit awards granted in the first quarter of 2020 and discussed under the section titled “Nonvested Equity Stock and Stock Units” below.