In millions, except per share items | Dec-31-21 | Dec-31-20 | Dec-31-19 | Dec-31-18 | Dec-31-17 | Dec-31-16 | Dec-31-15 | Dec-31-14 |
| 10-K | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K |
Cash flows from operating activities: | | | | | | | | |
Net loss | -61.9 | -21.6 | | | | | | |
Adjustments to reconcile net loss to net cash used in operating activities: | | | | | | | | |
Depreciation expense | 0.2 | 0.0 | | 0.6 | 0.3 | | | |
Amortization of intangible assets | 1.7 | 1.7 | | | | | | |
(Gain) loss on disposal of assets, net | | | 0.1 | 0.1 | | 0.0 | 0.0 | 0.0 |
Stock-based compensation | 12.8 | 1.3 | 3.0 | 4.7 | 3.2 | 0.6 | 0.2 | 0.2 |
Bad debt expense | 0.1 | 0.3 | | | | | | |
Deferred income tax | -0.1 | -0.1 | | | | | | |
Gain on changes in fair value of liability warrants | 2.8 | | | | 1.6 | 0.5 | 0.0 | -0.2 |
Other noncash items | | 0.0 | | | | | | |
Change in operating assets and liabilities, net of business combination: | | | | | | | | |
Accounts and other receivables | -0.3 | 1.2 | 0.6 | 3.4 | -4.2 | | 0.1 | 0.1 |
Inventory | -0.4 | -1.2 | 0.0 | -0.2 | -0.6 | -0.5 | 0.1 | -0.2 |
Prepaid expenses and other current assets | -0.4 | 0.8 | 0.4 | 0.1 | -0.5 | -1.0 | 0.0 | -0.1 |
Accounts payable and accrued liabilities | -1.5 | -1.0 | -3.5 | -0.6 | 2.6 | 1.3 | 1.4 | |
Warranty liability | -0.7 | 0.1 | | | | | | |
Other | 0.5 | 0.1 | | | | | | |
Net cash used in operating activities | -15.4 | -8.6 | -22.9 | -29.4 | -30.6 | -19.4 | -11.4 | -9.9 |
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Cash flows from investing activities: | | | | | | | | |
Proceeds from sale of capital assets | | | | | | | 0.0 | |
Cash (used in) provided by investing activities: | 1.9 | -2.4 | 2.4 | 19.5 | -21.9 | 6.2 | 2.8 | -7.9 |
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Cash flows from financing activities: | | | | | | | | |
Proceeds from sale and issuance of securities | | | 23.4 | 9.8 | | 67.2 | | |
Proceeds from warrants exercised | 45.6 | 0.7 | | | | | | |
Net cash provided by financing activities | 33.3 | 11.1 | 13.4 | 10.0 | 0.6 | 82.8 | 5.1 | 22.2 |
Effect of currency exchange rate changes on cash and cash equivalents | 0.0 | -0.1 | | | | | | |
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Proceeds from issuance of common stock warrant liabilities, net of issuance costs of $1,442 | | | | | | | | |
Noncash investing and financing activities: | | | | | | | | |
Capital expenditures accruals | 0.0 | 0.2 | 0.0 | 0.2 | 0.1 | 0.1 | | |