v3.22.4
Balance Sheet Components
 12 Months Ended
Dec. 31, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]  
Balance Sheet Components Balance Sheet Components
Marketable Securities
The following tables summarize the Company’s marketable securities by significant investment categories (in thousands):
December 31, 2022
Amortized CostUnrealized GainsUnrealized LossFair Value
Commercial paper$63,483 $— $— $63,483 
Agency debt securities5,762 17 — 5,779 
U.S. Treasury and government debt securities12,777 2 (28)12,751 
Total$82,022 $19 $(28)$82,013 
December 31, 2021
Amortized CostUnrealized GainsUnrealized LossFair Value
Commercial paper$50,954 $— $— $50,954 
U.S. Treasury and government debt securities26,203 — (36)26,167 
Total$77,157 $— $(36)$77,121 
The remaining contractual maturity of all marketable securities was within one year as of December 31, 2022 and 2021. Realized gains and losses were not material for the years ended December 31, 2022, 2021 and 2020. As of December 31, 2022 and 2021, there were no securities that were in an unrealized loss position for more than twelve months.
Property, Equipment and Software, Net
Property, equipment and software, net consisted of the following (in thousands):
December 31,
20222021
Internal-use software$40,794 $30,581 
Network hardware, computer equipment and software129,212 92,561 
Leasehold improvements4,026 2,426 
Furniture and fixtures2,087 1,448 
Property, equipment and software, gross176,119 127,016 
Less: accumulated depreciation and amortization(104,963)(76,876)
Total property, equipment and software, net$71,156 $50,140 
Depreciation and amortization expense related to property, equipment, and software (excluding amortization of internal use software) was $23.6 million, $15.7 million, and $9.8 million for the years ended December 31, 2022, 2021 and 2020, respectively.
The Company capitalized $14.5 million, $10.3 million, and $7.3 million in software development costs during the years ended December 31, 2022, 2021 and 2020, respectively. Fully-amortized software development costs of $4.3 million have been removed from internal-use software and accumulated depreciation and amortization for the year ended December 31, 2022. Amortization expense of internal use software was $10.0 million, $7.4 million, and $5.9 million for the years ended December 31, 2022, 2021 and 2020, respectively. These costs are included within cost of revenue in the consolidated statements of operations.
The Company did not recognize any impairment charges on its long-lived assets during the years ended December 31, 2022, 2021 and 2020 .
Accounts Payable
Accounts payable consisted of the following (in thousands):
December 31,
20222021
Payable to publishers$266,506 $235,440 
Trade payables10,908 8,881 
Total accounts payable$277,414 $244,321 
Accrued Liabilities
Accrued liabilities consisted of the following (in thousands):
December 31,
20222021
Accrued compensation$14,587 $17,271 
Accrued and other current liabilities4,349 1,509 
Total accrued liabilities$18,936 $18,780