INTANGIBLE ASSETS

6 Months Ended

Jun. 30, 2013

INTANGIBLE ASSETS

INTANGIBLE ASSETS

6. INTANGIBLE ASSETS

The Company’s intangible assets at June 30, 2013 consist of the $30.0 million registrational milestone fee paid to GSK (see Note 3 “Collaborative Arrangements” above for more information) and are considered finite-lived intangible assets with an estimated amortization period of 15 years. The amortization expense, which will be a reduction in revenue from collaborative arrangements over the next five years, is estimated to be $10.0 million. There was no amortization expense for the three months and six months ended June 30, 2013.