9. Common Stock

We were authorized to issue 300,000,000 shares of common stock with a par value of $0.0001 per share as of December 31, 2019 and 2018. Each share of common stock is entitled to one vote. The holders of common stock are also entitled to receive dividends from funds available, when and if declared by the board of directors, subject to the approval and priority rights of holders of all classes of preferred stock outstanding.

As of December 31, 2019 and 2018, we reserved shares of common stock for issuance as follows:



	As of December 31,
	2019	2018
Options outstanding	2,898,977	4,496,557
Unvested restricted stock units outstanding	12,639,066	12,303,913
Shares available for grant under the 2014 equity plan and 2015 inducement plan	1,301,881	2,337,545
Shares available for purchase under the Employee Stock Purchase Plan	378,525	364,762
Total	17,218,449	19,502,777

Repurchase Program

In October 2018, our Board of Directors approved a common stock repurchase program (“Repurchase Program”) whereby the Company is authorized to purchase up to a maximum of $25.0 million of its common stock, subject to compliance with applicable law and the limitations in the Company’s credit facilities on stock repurchases.

The authorization allows repurchases from time to time in the open market or in privately negotiated transactions. The amount and timing of repurchases made under the Repurchase Program will depend on a variety of factors, including available liquidity, cash flow and market conditions. Shares can be purchased through the Repurchase Program through October 2020, unless extended or shortened by our Board of Directors. The Repurchase Program does not obligate us to acquire any particular amount of common stock and the program may be modified or suspended at any time at our discretion. The repurchases would be funded from available working capital and are subject to compliance with the terms and limitations of the Company’s credit facilities.

In 2019, we repurchased 2,137,874 shares of common stock at an average price of $5.29 per share for a total cost of $11.3 million under the Repurchase Program. In 2018, we repurchased 821,888 shares of common stock at an average price of $4.66 per share for a total cost of $3.8 million under the Repurchase Program. The maximum remaining dollar value of shares yet to be purchased under the Repurchase Program was $9.9 million at December 31, 2019. This excludes shares repurchased to settle employee tax withholding related to the vesting of our stock-settled bonus and RSUs.