Balance Sheet Details | Note 3. Balance Sheet Details Short-term Investments Short-term investments consisted of the following (in thousands): At June 30, 2022 Maturity Amortized cost Unrealized Unrealized Estimated (in years) or cost gains losses fair value U.S. government bonds less than 2 $ 76,778 $ — $ (1,121) $ 75,657 U.S. government agency bonds less than 3 106,592 11 (2,510) 104,093 Bank certificates of deposit less than 2 10,500 — (34) 10,466 Corporate notes less than 3 54,379 — (1,066) 53,313 Asset-backed securities less than 2 27,408 — (273) 27,135 Municipal bonds less than 3 18,446 — (473) 17,973 Total $ 294,103 $ 11 $ (5,477) $ 288,637 At December 31, 2021 Maturity Amortized cost Unrealized Unrealized Estimated (in years) or cost gains losses fair value U.S. government agency bonds less than 3 123,803 8 (540) 123,271 U.S. government bonds less than 1 $ 76,765 $ — $ (240) $ 76,525 Bank certificates of deposit less than 1 12,500 1 (9) 12,492 Commercial paper less than 1 2,998 — (1) 2,997 Corporate notes less than 3 55,178 37 (183) 55,032 Asset-backed securities less than 2 23,761 44 (31) 23,774 Municipal bonds less than 3 19,350 — (98) 19,252 Total $ 314,355 $ 90 $ (1,102) $ 313,343 As of June 30, 2022 and December 31, 2021, the total amortized cost basis of the Company’s impaired available-for-sale securities exceeded its fair value by $5.5 million and $1.0 million, respectively. Unrealized losses on these investments were primarily due to changes in interest rates. The Company does not intend to sell these investments and it is not more likely than not that the Company will be required to sell these investments before recovery of their amortized cost basis. Accordingly, no allowance for credit losses was recognized as of June 30, 2022 or December 31, 2021. Accounts Receivable, Net Accounts receivable consisted of the following (in thousands): June 30, December 31, 2022 2021 Accounts receivable $ 37,188 $ 34,805 Allowance for credit losses (1,156) (1,367) $ 36,032 $ 33,438 The Company’s allowance for credit losses represents management’s estimate of current expected credit losses and there were immaterial bad-debt write offs charged during the three and six months ended June 30, 2022. Additionally, no customers accounted for more than 10% of net accounts receivable as of June 30, 2022 or December 31, 2021. Inventory Inventory consisted of the following (in thousands): June 30, December 31, 2022 2021 Finished goods $ 12,840 $ 6,495 Work in process 4,918 7,010 Raw material 10,084 9,506 $ 27,842 $ 23,011 Accrued Liabilities Accrued liabilities consisted of the following (in thousands): June 30, December 31, 2022 2021 Accrued bonuses $ 9,481 $ 17,015 Accrued vacation benefits 4,631 4,196 Accrued Employee Stock Purchase Plan liability 3,959 2,419 Accrued payroll taxes 3,698 1,693 Other accrued liabilities 26,445 30,704 $ 48,214 $ 56,027 |