6. PATENT COSTS

We amortize intangible assets with definite lives on a straight-line basis over their estimated useful lives, ranging from 1 to 13 years, and review for impairment on a quarterly basis and when events or changes in circumstances indicate that the carrying amount of such assets may not be recoverable.

For the three months ended March 31, 2014, we increased our capitalized patent costs by $151,000 based on the most current information reported to us by Auxilium. As of March 31, 2014, the Company’s estimated capitalized costs related to certain patent costs paid by Auxilium on behalf of the Company are approximately $192,000, which are reimbursable to Auxilium under the Auxilium Agreement. These patent costs are creditable against future royalty revenues. For each period presented below net patent costs consisted of:

	March 31,			December 31,
	2014			2013
Patents	$	623,828		$	472,375
Accumulated Amortization		(301,221	)		(256,376	)
	$	322,607		$	215,999

The amortization expense for patents for the three months ended March 31, 2014 was approximately $45,000. In the comparable period of 2013, the amortization expense for patents was approximately $16,000. The estimated aggregate amortization expense for each of the next five years is approximately as follows:

2015	$	38,000
2016		32,000
2017		32,000
2018		32,000
2019		32,000