Cost of goods sold during the quarter ended June 30, 2013 was $2.8 million as compared to $1.3 million for the quarter ended March 31, 2013. Gross margin as a percentage of net revenues improved from 45% to 48% in the second quarter as compared to the first quarter of 2013. The majority of Vascepa capsules sold during the six months ended June 30, 2013 included API sourced from a single API supplier. Amarin's purchases of API from this supplier in 2012 and early 2013 are at higher cost per kilogram than expected future purchases from this supplier. The unusually high cost of goods, as a percentage of revenue, is attributable to a number of things including the geographic location of our suppliers, exchange rate exposures and lower volume and less favorable economic terms than those with other API suppliers. Amarin expects steady state gross margin as a percentage of product revenues to approach the high seventies to low eighties as it increases purchase volumes and sources lower cost API. In April 2013, sNDAs were approved for two comparatively lower cost API suppliers, BASF and Chemport Inc. While current inventory is comprised primarily of inventory from the initial supplier, unless the company secures substantial price concessions from the initial supplier, it anticipates shifting a substantial portion of future API purchases to these lower cost suppliers.
Under U.S. GAAP, Amarin reported a net loss of $39.8 million in the second quarter of 2013, or basic and diluted loss per share of $0.26. This net loss included $5.1 million in non-cash, share-based compensation expense, $1.0 million in non-cash, warrant compensation income, and a $18.8 million gain on the change in the fair value of derivatives. In the second quarter of 2012, GAAP net loss was $53.9 million, or basic and diluted loss per share of $0.38, and included $4.8 million in non-cash share-based compensation expense, $1.9 million in non-cash warrant compensation expense, and a $18.9 million loss on the change in the fair value of derivatives.