Stock-Based Compensation

9 Months Ended

Sep. 30, 2018

Note 5. Stock-Based Compensation

Common Stock and Stock‑Based Awards

The Company has authorized common stock of 200,000,000 shares, par value $0.00001 per share. In June 2018 the Company amended its certificate of incorporation to increase the total number of authorized shares of common stock from 100,000,000 shares to 200,000,000 shares.

On November 8, 2018, the Company issued a press release announcing that its Board of Directors has authorized a $150 million common stock repurchase program (the “Share Repurchase Program”) pursuant to which the Company may, from time to time, repurchase shares of common stock on the open market (either with or without a 10b5-1 plan) or through privately negotiated transactions. The Share Repurchase Program has no time limit and may be suspended or discontinued at any time without notice. There is no minimum number of shares of common stock that the Company is required to repurchase under the Share Repurchase Program.

Total stock-based compensation expense in the accompanying consolidated statements of operations totaled $2.5 million and $1.4 million during the three months ended September 30, 2018 and 2017, respectively, and $9.6 million and $4.5 million during the nine months ended September 30, 2018 and 2017, respectively.

A summary of the RSU and RSA activity for the nine months ended September 30, 2018 is presented in the following table:

	Restricted Stock Units						Restricted Stock Awards
	Units				Weighted- Average Grant Date Fair Value		Units				Weighted- Average Grant Date Fair Value
					(in millions)						(in millions)
Unvested outstanding as of December 31, 2017		1,579,499		$		12.25		10,809		$		19.13
Granted		317,904				32.97		—				—
Vested		(783,672	)			8.05		(10,809	)			19.13
Canceled		(9,885	)			19.13		—				—
Unvested outstanding as of September 30, 2018		1,103,846		$		21.14		—		$		—

A summary of the ERI Stock Option activity for the nine months ended September 30, 2018 is presented in the following table:

				Weighted-
				Average
				Exercise
	Options			Price

Outstanding as of December 31, 2017		271,852		$	9.63
Expired		(15,776	)		10.89
Exercised		(120,120	)		9.09
Outstanding as of September 30, 2018		135,956		$	9.96

As of September 30, 2018, 119,505 options were exercisable.