| In millions, except per share items | Jun-30-23 | Mar-31-23 | Dec-31-22 | Jun-30-22 | Mar-31-22 | Dec-31-21 | Sep-30-21 | Jun-30-21 |
| | 10-Q | 8-K | 8-K | 10-Q | 10-Q | 8-K | 10-Q | 10-Q |
| Cash flows from operating activities: | | | | | | | | |
| Net loss | -22.9 | -21.9 | | -15.6 | -5.7 | | -3.9 | -90.4 |
| Adjustments to reconcile net loss to net cash used in operating activities: | | | | | | | | |
| Depreciation and amortization | 1.0 | 1.1 | | 0.5 | | | | 0.3 |
| Non-cash interest (income) expense | -1.5 | | | 0.0 | | | | |
| Non-cash lease expense | 0.6 | | | 0.3 | 0.3 | | | |
| Stock-based compensation expense | 2.7 | 2.1 | | 2.9 | 2.8 | | | 0.2 |
| Change in fair value of common stock warrant liabilities | -0.6 | | | -9.4 | -15.7 | | 2.2 | 6.4 |
| Other non-cash income and expenses, net | 0.0 | | | 0.2 | | | | 0.0 |
| Changes in operating assets and liabilities: | | | | | | | | |
| Accounts receivable, net | 0.3 | 4.3 | | 1.1 | 0.8 | | | |
| Prepaid expenses and other assets | 2.6 | 0.0 | | 0.9 | 0.4 | | | -2.3 |
| Accounts payable | -0.1 | -0.5 | | 0.8 | -1.6 | | | -0.5 |
| Accrued and other current liabilities | | | | | | | | |
| Accrued product warranties | | | | | | | | |
| Deferred revenue | | | | | | | | |
| Operating lease liabilities | | | | | | | | |
| Net cash used in operating activities | -19.0 | -18.5 | | -15.2 | -19.4 | | -1.7 | -8.5 |
| |
| Cash flows from investing activities: | | | | | | | | |
| Purchases of property and equipment | -3.4 | | | -4.4 | -4.0 | | | 0.0 |
| Maturities and purchases of short-term investments, net | 37.4 | | | -79.6 | | | | |
| Net cash provided by (used in) investing activities | -38.1 | 72.1 | | -84.0 | -4.0 | | | 0.0 |
| |
| Cash flows from financing activities: | | | | | | | | |
| Payments on notes payable | -0.8 | | | -0.5 | -0.5 | | | -0.1 |
| Proceeds from stock options exercised | 0.4 | 0.1 | | 0.0 | 0.0 | | | 0.1 |
| Proceeds from contributions to Employee Stock Purchase Plan | 0.3 | | | | | | | |
| Repurchase of shares from employees for income tax withholding purposes | -0.1 | | | | -2.8 | | | |
| Other, net | 0.0 | | | 0.0 | | | | |
| Net cash used in financing activities | -0.1 | -0.3 | | -0.4 | -3.2 | | | 0.0 |
| Net change in cash, cash equivalents and restricted cash | -4.1 | | | -99.6 | -26.7 | | | -8.5 |
| Cash, cash equivalents and restricted cash, beginning of period | | | 0.0 | | | | | |
| Cash, cash equivalents and restricted cash, end of period | | | 0.0 | | | | | |
| |
| Supplemental disclosures of cash flow information: | | | | | | | | |
| Cash paid for operating leases included in cash used in operating activities | 0.8 | | | 0.4 | 0.4 | | | |
| Non-cash investing and financing transactions: | | | | | | | | |
| Purchase of property and equipment included in accounts payable and accrued and other current liabilities | 0.9 | | | -1.7 | 2.2 | | | 0.0 |
| Right-of-use operating lease assets obtained in exchange for lease obligations | | | | | 4.5 | | | |
| Right-of-use finance lease assets obtained in exchange for lease obligations | | | | | 0.1 | | | |
| Cash and cash equivalents | | | | | | | | |
| Restricted cash, current | | | | | | | | |
| Restricted cash, non-current | | | | | | | | |
| Total cash, cash equivalents and restricted cash shown in the condensed consolidated statements of cash flows | | | 0.0 | | | | | |