Capitalized software development costs consisted of the following (in thousands):

Gross

carrying

amount

Amortization

period

Accumulated

amortization

Net

carrying

amount

As of December 31, 2020

59,761

3 years

(43,432

)

16,329

As of December 31, 2019

49,909

3 years

(35,622

)

14,287

The Company capitalized software development costs of $9.9 million, $8.8 million and $8.8 million during the years ended December 31, 2020, 2019 and 2018, respectively.

Amortized expense for capitalized software development costs was $7.9 million, $7.0 million and $5.9 million during the years ended December 31, 2020, 2019 and 2018, respectively. Amortization of capitalized software development costs is classified within cost of revenue in the consolidated statements of operations and comprehensive loss.

The expected amortization, as of December 31, 2020, for each of the next three years is as follows (in thousands):

2021	$	7,610
2022		5,682
2023		3,037
	$	16,329