| Dec 31, 2011 | Dec 31, 2012 | Dec 31, 2013 | Dec 31, 2014 | Dec 31, 2015 | Dec 31, 2016 | Dec 31, 2017 | Dec 31, 2018 | Dec 31, 2019 | Dec 31, 2020 | Dec 31, 2021 | Dec 31, 2022 | Dec 31, 2023 |
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| Cash and cash equivalents | 3 | 3 | 1 | 32 | 12 | 9 | 12 | 8 | 6 | 18 | 30 | 4 | 7 |
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| Accounts Receivable, after Allowance for Credit Loss, Current | 9 | 12 | 11 | 9 | 9 | 10 | 10 | 11 | 9 | 3 | 4 | 6 | 6 |
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| Inventory | 11 | 11 | 11 | 13 | 13 | 14 | 12 | 12 | 11 | 11 | 13 | 16 | 11 |
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| Prepaid expenses and other current assets | 2 | 2 | 2 | 2 | 1 | 2 | 2 | 2 | 1 | 3 | 2 | 3 | 1 |
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| Total current assets | 25 | 27 | 26 | 55 | 35 | 34 | 36 | 33 | 27 | 35 | 49 | 29 | 25 |
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| Property, Plant and Equipment, Net | 1 | 2 | 2 | 1 | 4 | 4 | 4 | 2 | 1 | 1 | 1 | 4 | 6 |
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| Goodwill | 3 | 3 | 3 | 3 | 3 | 3 | 3 | 3 | 3 | 3 | 3 | 3 | 3 |
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| Right-of-use assets, leases | - | - | - | - | - | - | - | - | 0 | 2 | 2 | 2 | 2 |
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| Other assets | 0 | 0 | 0 | 0 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
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| Total assets | 30 | 32 | 31 | 59 | 42 | 42 | 43 | 39 | 32 | 41 | 55 | 38 | 35 |
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| Accounts payable | 8 | 8 | 9 | 8 | 6 | 9 | 5 | 6 | 5 | 3 | 3 | 6 | 6 |
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| Accrued liabilities | 6 | 6 | 5 | 5 | 6 | 6 | 6 | 8 | 5 | 7 | 8 | 9 | 9 |
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| Deferred Revenue, Current | 2 | 3 | 3 | 2 | 3 | 3 | 3 | 2 | 2 | 2 | 2 | 2 | 2 |
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| Medium-term Notes, Current | - | - | - | - | - | - | - | - | - | - | - | 1 | 2 |
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| Total current liabilities | 16 | 19 | 22 | 16 | 15 | 18 | 13 | 16 | 26 | 11 | 14 | 18 | 20 |
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| Deferred revenue | 0 | 0 | 0 | - | 0 | 0 | 0 | - | 0 | 0 | 0 | 0 | 0 |
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| Warranty accrual | - | - | - | 1 | 1 | 1 | 0 | 0 | 0 | 0 | 1 | 0 | 1 |
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| Medium-term Notes, Noncurrent | - | - | - | - | - | - | - | - | - | - | 14 | 13 | 12 |
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| Non-current operating lease liability | - | - | - | - | - | - | - | - | - | 2 | 1 | 1 | 1 |
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| Other liabilities | 0 | 0 | - | - | 0 | 0 | 0 | 0 | 1 | 1 | 0 | 0 | 0 |
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| Total liabilities | 17 | 20 | 23 | 17 | 17 | 20 | 14 | 27 | 28 | 31 | 30 | 33 | 33 |
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| Series H Preferred Stock | - | - | - | - | - | - | - | - | - | - | - | - | 0 |
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| Series J Convertible Preferred Stock | - | - | - | - | - | - | - | - | - | - | - | - | 2 |
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| Series H Preferred Stock | - | - | - | - | - | - | - | - | - | - | - | - | 0 |
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| Total mezzanine equity | - | - | - | - | - | - | - | - | 4 | - | - | - | 2 |
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| Common Stock, Value, Issued | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
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| Additional paid-in capital, common stock | 139 | - | - | 185 | 189 | 201 | 225 | 228 | 236 | 262 | 293 | 302 | 317 |
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| Accumulated other comprehensive loss | -0 | -0 | -0 | -1 | -1 | -1 | -1 | -1 | -1 | -0 | -1 | -1 | -1 |
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| Accumulated deficit | -109 | -112 | -124 | -143 | -163 | -178 | -195 | -217 | -235 | -251 | -268 | -296 | -317 |
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| Total stockholders' equity | 13 | 12 | 8 | 42 | 25 | 22 | 29 | 11 | 0 | 10 | 25 | 5 | -0 |
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| Total liabilities, convertible redeemable preferred stock and stockholders' equity (deficit) | 30 | 32 | 31 | 59 | 42 | 42 | 43 | 39 | 32 | 41 | 55 | 38 | 35 |
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