I found this:

"If you decide to amortize your patent rather than deduct expenses in the first year they were incurred, the patent falls under the category of intangibles for IRS purposes. These expenses are usually amortized or written off over the period for which the asset is in use, generally for 15 years. Amortization is similar to depreciation and may end up saving you money instead of choosing to deduct all expenses in one year. Consult with an accountant experienced in patent law to decide whether amortization or deduction makes the most sense for you."