| May 31, 2012 | May 31, 2013 | May 31, 2014 | May 31, 2015 | May 31, 2016 | May 31, 2017 | May 31, 2018 | May 31, 2019 | May 31, 2020 | May 31, 2021 | May 31, 2022 | May 31, 2023 | May 31, 2024 |
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| Net income | -3 | -3 | 0 | -7 | -7 | -6 | 1 | -5 | -3 | -2 | 9 | 15 | 33 |
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| Stock-based compensation expense | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 3 | 3 | 3 |
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| Depreciation and amortization | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 |
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| Deferred income taxes | - | - | - | - | - | - | - | - | - | - | - | - | -21 |
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| Accretion of investment discount | - | - | - | - | - | - | - | - | - | - | - | -1 | 0 |
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| Amortization of operating lease right-of-use assets | - | - | - | - | - | - | - | - | - | - | - | - | 1 |
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| Accounts receivable | -1 | -0 | -1 | 2 | 1 | -4 | 1 | -2 | -1 | 1 | -8 | - | -7 |
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| Inventories | -1 | 1 | -1 | -1 | 0 | 0 | -2 | -0 | -1 | 1 | -7 | -9 | 14 |
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| Prepaid expenses and other current assets | - | - | - | - | - | - | - | - | - | - | - | - | 1 |
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| Accounts payable | 1 | 0 | 1 | -1 | 1 | 2 | -1 | 0 | -1 | 2 | 1 | 5 | -4 |
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| Accrued expenses | 0 | 0 | -0 | -0 | 1 | 0 | 0 | 0 | -1 | 1 | 1 | 1 | -1 |
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| Deferred revenue | - | - | - | - | - | - | - | - | - | - | - | - | -1 |
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| Operating lease liabilities | - | - | - | - | - | - | - | - | - | - | - | 6 | -0 |
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| Income taxes payable | -0 | -0 | -0 | -0 | -0 | 0 | -0 | -0 | -0 | -0 | 0 | 0 | 0 |
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| Net cash provided by operating activities | -5 | -0 | -1 | -2 | -6 | -4 | -1 | -6 | -2 | -3 | 2 | 10 | 2 |
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| Proceeds from maturities of investments | - | - | - | - | - | - | - | - | - | - | - | 16 | 18 |
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| Purchases of investments | - | - | - | - | - | - | - | - | - | - | - | 33 | - |
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| Purchases of property and equipment | 0 | 0 | 0 | 0 | 1 | 0 | 1 | 0 | 0 | 0 | 0 | 1 | 1 |
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| Net cash provided by (used in) investing activities | 1 | -0 | -0 | -0 | -1 | -0 | -1 | -0 | -0 | -0 | -0 | -19 | 17 |
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| Proceeds from issuance of common stock under employee plans | 0 | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 4 | 3 | 2 |
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| Shares repurchased for tax withholdings on vesting of restricted stock units, amount | - | - | - | - | - | - | - | - | 0 | 0 | 0 | 2 | 2 |
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| Proceeds from issuance of common stock, net of issuance costs | - | - | - | - | - | - | - | - | - | - | 24 | - | -0 |
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| Net cash provided by financing activities | 2 | 1 | 0 | 6 | 3 | 22 | 1 | -6 | 2 | 2 | 26 | 7 | 0 |
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| Effect of exchange rate changes on cash, cash equivalents and restricted cash | - | - | - | - | - | - | - | - | - | - | - | -0 | -0 |
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| Net increase (decrease) in cash, cash equivalents and restricted cash | - | - | - | - | - | - | - | - | 0 | -1 | 27 | -1 | 19 |
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| Income taxes paid | - | - | - | - | - | - | - | 0 | 0 | 0 | - | - | 0 |
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| Interest paid | - | - | - | - | - | - | - | 1 | - | 0 | 0 | - | - |
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| Net transfer of equipment between inventory and property and equipment | - | - | - | - | - | - | - | - | - | - | - | 1 | 0 |
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