In July 2014, we completed an underwritten registered offering pursuant to which we sold 5,559,866 Series A units at a price per unit of $3.48 and 1,340,538 Series B units at a price per unit of $3.47.

Each Series A unit consisted of one share of common stock and a Series A warrant to purchase up to one-half of one share of common stock at an initial exercise price of $4.00 per share. Each Series A warrant is exercisable at any time on or after the date of issuance until the fifth anniversary of the issuance of the Series A warrants.

The Series B units were offered and sold to those purchasers whose purchase of Series A units in the offering would have resulted in the purchaser, together with its affiliates and certain related parties, beneficially owning more than 9.99% of our outstanding common stock following the completion of the offering. Each Series B unit consisted of a Pre-Funded Series B warrant to purchase up to one share of common stock at an initial exercise price of $0.01 per share and a Series B warrant to purchase up to one-half of one share of common stock at an initial exercise price of $4.00 per share. Each Pre-Funded Series B warrant and Series B warrant is exercisable at any time on or after the date of issuance until the fifth anniversary of the issuance of the Pre-Funded Series B warrants and Series B warrants, respectively.

We received net proceeds of approximately $22.4 million, after deducting the underwriting discount and offering expenses. Of the $22.4 million in net proceeds, $3.2 million was received in advance of the completion of the transaction on June 30, 2014 and has been recognized on the consolidated balance sheet under current liabilities as Proceeds received in advance.