Intangible assets as of December 31, 2014 reflect the purchase price attributable to patents in connection with the 1998 acquisition of BioSeq, Inc. and the PCT business. Acquired PCT patents were being amortized to expense on a straight line basis at the rate of $48,632 per year over their estimated remaining useful lives of approximately 6 years. We performed a review of our intangible assets for impairment. When impairment is indicated, any excess of carrying value over fair value is recorded as a loss. We have concluded that there is no impairment of intangible assets. Intangible assets at December 31, 2014 and 2013 consisted of the following:

Amortization expense for the year ended December 31, 2013 was $48,632 and for the year ended December 31, 2014 was $36,498, at which time the assets were fully amortized.