Identifiable intangible assets
The Company's identifiable intangible assets represent intangible assets acquired in the Brink Acquisition, the Drive-Thru Acquisition, the Restaurant Magic Acquisition and software development costs. The Company capitalizes certain software development costs for software used in its Restaurant/Retail reporting segment. Software development costs incurred prior to establishing technological feasibility are charged to operations and included in research and development costs.
The technological feasibility of a software product is established when the Company has completed all planning, designing, coding, and testing activities that are necessary to establish that the software product meets its design specifications, including functionality, features, and technical performance requirements.
Software development costs incurred after establishing technological feasibility for software sold as a perpetual license, (as defined within ASC 985-20, Software – "Costs of Software to be sold, Leased, or Marketed" - for software cost related to sold as a perpetual license) are capitalized and amortized on a product-by-product basis when the software product is available for general release to customers.
Included in "Acquired and internally developed software costs" in the table below are approximately $2.5 million and $3.0 million of costs related to software products that have not satisfied the general release threshold as of December 31, 2019 and December 31, 2018, respectively. These software products are expected to satisfy the general release threshold within the next 12 months.
Software development is also capitalized in accordance with ASC 350-40, “Intangibles - Goodwill and Other - Internal - Use Software,” and is amortized over the expected benefit period, which generally ranges from three to seven years. Long-lived assets are tested for impairment when events or conditions indicate that the carrying value of an asset may not be fully recoverable from future cash flows. Software costs capitalized during the years ended 2019 and 2018 were $4.1 million and $3.9 million, respectively.
Annual amortization charged to cost of sales when a product is available for general release to customers is computed using the greater of (a) the straight-line method over the remaining estimated economic life of the product, generally three to seven years or (b) the ratio that current gross revenues for a product bear to the total of current and anticipated future gross revenues for that product. Amortization of capitalized software costs amounted to $3.3 million and $3.5 million, in 2019 and 2018, respectively.
The components of identifiable intangible assets, excluding discontinued operations, are:
Table:
 | December 31, |  | 
 | (in thousands) |  | 
 | 2019 | 2018 | Estimated Useful Life
Acquired and internally developed software costs | $36,137 | $18,972 | 3 - 7 years
Customer relationships | 4,860 | 160 | 7 years
Non-compete agreements | 30 | 30 | 1 year
 | 41,027 | 19,162 | 
Less accumulated amortization | (12,389) | (11,708) | 
 | $28,638 | $7,454 | 
Internally developed software costs not meeting general release threshold | 2,500 | 3,005 | 
Trademarks, trade names (non-amortizable) | 1,810 | 400 | Indefinite
 | $32,948 | $10,859 | 


Question: What is the change in Acquired and internally developed software costs from December 31, 2018 and 2019?
Answer: 17165
Calculation: 36,137-18,972