| In millions, except per share items | Dec-31-22 | Dec-31-21 | Dec-31-20 | Dec-31-19 | Dec-31-18 | Dec-31-17 | Dec-31-16 |
| | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K | S-1/A |
| Operating activities: | | | | | | | |
| Adjustments to reconcile net loss to net cash used by operating activities: | | | | | | | |
| Depreciation and amortization expense | 9.6 | 3.4 | 1.5 | 1.1 | 1.3 | 1.5 | |
| Non-cash lease expense | 0.5 | 0.7 | | | | | |
| Net realized loss (gain) on investments | 0.1 | | | | | | |
| Stock-based compensation | 22.4 | 9.7 | 1.6 | 1.3 | 1.2 | 0.4 | |
| Change in fair value of contingent consideration | 0.3 | 0.1 | | | | | |
| Cost of leased equipment sold to customer | 0.2 | 0.6 | | | | | |
| Changes in operating assets and liabilities: | | | | | | | |
| Accounts receivable | -2.9 | -0.5 | 2.1 | -2.4 | -0.9 | -1.8 | |
| Inventory | -23.7 | -15.9 | -4.2 | -3.6 | -0.4 | -0.3 | |
| Prepaid expenses and other current assets | -3.2 | -1.3 | -1.0 | -0.2 | 0.2 | 0.8 | |
| Other assets | -1.1 | -0.6 | | | | | |
| Accounts payable | 1.9 | 6.8 | -1.8 | 1.4 | -1.0 | 1.5 | |
| Accrued expenses and contract liabilities | 0.4 | 4.0 | 1.5 | -0.1 | -0.2 | -0.1 | |
| Net cash used in operating activities | -124.8 | -71.9 | -38.3 | -29.5 | -19.9 | -20.8 | |
| |
| Investing Activities: | | | | | | | |
| Purchases of property and equipment | -2.4 | -0.8 | | | | | |
| Purchase of available for sale securities | -84.2 | -313.4 | | | | | |
| Sale and maturity of available for sale securities | 200.9 | 86.5 | | | | | |
| Construction in progress | -0.8 | -0.6 | | | | | |
| Sale of property and equipment | 0.0 | | | | | | |
| Net cash provided by investing activities | 82.8 | -278.1 | -2.5 | -0.1 | -0.3 | -1.0 | |
| |
| Financing activities: | | | | | | | |
| Proceeds from sale of common stock | 23.1 | 342.7 | 39.9 | 19.6 | 19.4 | | |
| Offering expenses on sale of common stock | -0.6 | -1.7 | -2.0 | | | | |
| Proceeds from warrant and option exercises | 0.3 | 10.0 | 28.7 | 0.9 | 0.0 | | |
| Net cash provided by financing activities | 23.0 | 336.1 | 61.9 | 30.4 | 35.8 | 17.6 | |
| Effect of exchange rates on cash, cash equivalents and restricted cash | 0.0 | | | | | | |
| |
| Reconciliation of cash, cash equivalents and restricted cash reported within the unaudited condensed consolidated balance sheets to the total amounts reported on the unaudited condensed consolidated statements of cash flows | | | | | | | |
| Cash and cash equivalents | | | | | | | |
| Restricted cash | | | | | | | |
| |
| Supplemental cash flow disclosures: | | | | | | | |
| Cash paid for interest | 0.3 | 1.9 | 1.3 | 1.3 | 0.7 | 0.5 | |
| Cash paid for operating lease liabilities | 1.6 | 0.4 | | | | | |
| Supplemental disclosure of non-cash investing and financing activities: | | | | | | | |
| Property and equipment included in accounts payable | 0.1 | | | | 0.0 | 0.0 | |