Preferred and Common Stock
12 Months Ended
Dec. 31, 2014
Stockholders' Equity Note [Abstract]  
Preferred and Common Stock
Preferred and Common Stock
Preferred Shares
The Board of Directors has the authority to designate up to 5.0 million shares of preferred stock in one or more series and to define the terms of each series of preferred stock, including dividend, conversion, voting, redemption and liquidation rights and preferences. As of December 31, 2014 no preferred stock has been issued or is outstanding.
Stock Purchase Rights Agreement
The Company has a Rights Agreement to protect stockholders' interest in the event of a proposed takeover of the Company. Each outstanding share of common stock has attached to it one preferred share purchase right, or Right, which entitles the registered holder to purchase one one-hundredth of a share of Series A Preferred Stock at a price of $120.00 subject to adjustment. The rights are exercisable only if a person, entity or group acquires, or announces their intention to acquire beneficial ownership of 15% or more of outstanding common stock, or Acquiring Person. Upon exercise, holders, other than the Acquiring Person, will have the right to receive shares of common stock or Series A Preferred Shares, cash, debt, stock or a combination thereof having a market value of two times the exercise price of the Right. The Rights expire on March 20, 2019.
Common Shares
As of December 31, 2014, the Company has authorized 185.0 million shares of common stock, of which 16.4 million shares are available for future issuance.
Common shares reserved for future issuance upon the exercise, issuance or conversion of the respective equity instruments at December 31, 2014 are as follows (in thousands):
Stock options:
 
  Issued and outstanding
11,116

  Available for future grant
8,611

Issued and outstanding restricted stock units
1,674

Available for issuance under the ESPP
1,388

Warrants outstanding
250

Convertible Senior Notes
28,088

Total
51,127


On January 25, 2012, the Company closed an underwritten public offering of 15.0 million shares of common stock at $4.15 per share, resulting in gross proceeds of $62.0 million. After deducting $3.8 million in underwriting discounts and commissions and other offering costs, net proceeds were $58.2 million.