v3.22.2.2
Condensed Statement of Cash Flows (Unaudited) - USD ($)
$ in Thousands
 9 Months Ended
Sep. 30, 2022
Sep. 30, 2021
Cash flows from operating activities:    
Net loss $ (121,512) $ (90,703)
Adjustments to reconcile net loss to net cash used in operating activities:    
Stock-based compensation expense 19,850 12,653
Depreciation and amortization 3,900 3,866
Non-cash lease expense 826 759
Non-cash interest expense 426 426
Accretion of discount on investments, net 1,081 1,173
Provision for inventories 1,617 766
Other non-cash items 26 5
Changes in operating assets and liabilities:    
Accounts receivable 3,079 (12,838)
Inventories (17,692) (17,925)
Prepaid expenses and other assets 728 718
Accounts payable (575) (2,151)
Accrued payroll and related benefits (5,675) 913
Accrued expenses and other current liabilities 2,476 3,496
Accrued warranty liability (248) 321
Deferred revenue 1,315 1,550
Operating lease liabilities (844) (617)
Net cash used in operating activities (111,222) (97,588)
Cash flows from investing activities:    
Purchases of property and equipment (6,216) (2,257)
Purchases of investment securities (168,615) (148,132)
Sales and maturities of investment securities 160,284 24,300
Net cash used in investing activities (14,547) (126,089)
Cash flows from financing activities:    
Proceeds from stock option exercises and employee stock purchase plan purchases 7,433 10,128
Proceeds from issuance of common stock upon follow-on public offering, net of issuance costs 0 149,085
Payment of deferred financing costs (135) 0
Net cash provided by financing activities 7,298 159,213
Net decrease in cash, cash equivalents and restricted cash (118,471) (64,464)
Cash, cash equivalents and restricted cash as of beginning of period 215,659 328,283
Cash, cash equivalents and restricted cash as of end of period 97,188 263,819
Supplemental cash flow disclosures:    
Cash paid for income taxes 334 72
Cash paid for interest 1,044 858
Cash paid for amounts included in the measurement of operating lease liabilities 844 617
Supplemental non-cash investing and financing activities:    
Capital expenditures included in accounts payable and accrued expenses 556 218
Transfer of inventories to property and equipment 0 1,392
Transfer Of Property And Equipment To Inventories $ 0 $ 146