The following table summarizes information relating to the Company’s definite-lived intangible assets:

The intangible assets noted above are amortized on a straight-line basis over their estimated useful lives with the exception of customer relationships which are being amortized using an accelerated method. The Company has only one definite-lived permit that is subject to amortization.

The following table summarizes the expected amortization over the next five years for our definite-lived intangible assets (including the one definite-lived permit):

Amortization expense relating to the definite-lived intangible assets as discussed above was $84,000 and $253,000 for the three and nine months ended September 30, 2018, respectively, and $93,000 and $281,000 for the three and nine months ended September 30, 2017, respectively.