The figures in the most recent (424B5) filing --- 51,475,368 shares of class A common stock and 8,885 shares of class B common stock outstanding as of May 19, 2015 --- exclude:
3,072,495 shares of Class A common stock reserved for issuance upon the exercise of employee and director options outstanding.
2,462,479 shares of Class A common stock reserved for issuance under existing option plans.
1,075,674 shares of Class A common stock reserved for issuance under employee stock purchase plan.
6,974,945 shares of Class A common stock reserved for the exercise of warrants outstanding prior to this offering.