| 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 |
|---|
| Net loss | -4 | -33 | -30 | - | -12 | -54 | -55 | -33 | -63 |
|---|
| Depreciation and amortization | - | - | - | - | - | - | - | 0 | 1 |
|---|
| Stock-based compensation expense | - | - | - | - | - | - | - | - | 4 |
|---|
| Accretion of investment discount | - | - | - | - | - | - | - | - | 0 |
|---|
| Amortization of debt issuance costs and discount | 1 | - | 0 | 0 | 0 | 1 | 1 | 1 | 2 |
|---|
| Fair Value Adjustment of Warrants | -10 | - | 2 | -3 | -12 | 4 | 5 | -30 | -22 |
|---|
| Change in fair value of derivative liabilities | - | - | - | - | - | 2 | 2 | 1 | 1 |
|---|
| Noncash operating lease expense for right-of-use asset | - | - | - | - | - | - | - | - | 0 |
|---|
| Loss on extinguishment of debt | -1 | - | - | - | - | -1 | -2 | -3 | - |
|---|
| Prepaid expenses, other assets, deferred costs, and other | 0 | 1 | -0 | 1 | 6 | -3 | 1 | -2 | -2 |
|---|
| Accounts receivable | 0 | -0 | - | - | - | - | - | 1 | 1 |
|---|
| Inventory | - | - | - | - | - | - | - | 5 | 0 |
|---|
| Accounts payable | - | - | - | - | - | - | - | 3 | -1 |
|---|
| Accrued expenses, other liabilities, and other | - | - | - | - | - | - | - | 5 | 2 |
|---|
| Net cash used in operating activities | - | -25 | -29 | -25 | -28 | -38 | -49 | -55 | -80 |
|---|
| Purchase of intangible assets | - | - | - | - | - | - | - | 1 | 0 |
|---|
| Purchase of investments | - | - | 36 | 78 | 85 | 40 | 14 | - | 27 |
|---|
| Net cash used in investing activities | - | 2 | -22 | -10 | -1 | 26 | 6 | -1 | -27 |
|---|
| Proceeds from common stock issued | 62 | 41 | 28 | 10 | 32 | 46 | 91 | 39 | 47 |
|---|
| Payments of offering costs and underwriting discounts and commissions | - | - | - | - | - | 3 | 6 | 0 | 4 |
|---|
| Proceeds from loan payable | - | - | - | - | - | - | - | 30 | 5 |
|---|
| Payments of loan payable issuance costs | - | - | - | - | - | - | - | 1 | 0 |
|---|
| Proceeds from employee stock purchase plan issuances | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
|---|
| Repurchase of shares to satisfy tax withholdings | - | - | - | - | - | - | - | -0 | - |
|---|
| Proceeds from Convertible Debt | - | - | - | - | - | 16 | 10 | - | - |
|---|
| Payments of senior convertible notes issuance costs | - | - | 1 | - | - | 1 | 0 | - | - |
|---|
| Net cash provided by financing activities | - | 38 | 40 | 10 | 29 | 42 | 94 | 67 | 49 |
|---|
| Net (decrease) increase in cash, cash equivalents, and restricted cash | - | - | - | - | 0 | 30 | 51 | 11 | -59 |
|---|
| Cash paid for interest | - | - | - | - | 2 | 1 | 1 | 2 | 5 |
|---|
| Cash received for interest | - | - | 0 | 1 | 1 | 1 | 0 | 0 | 1 |
|---|
| Capital Expenditures Incurred but Not yet Paid | - | - | - | - | - | - | - | 0 | - |
|---|
| Deferred offering and issuance costs included in accounts payable | - | - | - | - | - | - | 0 | 0 | - |
|---|
| Deferred offering costs reclassified to additional paid-in capital | 4 | 3 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
|---|
| Stock Issued | - | - | - | - | - | 3 | 5 | 7 | - |
|---|
| Common stock issued for Commitment Shares | - | - | - | - | - | - | 1 | - | - |
|---|
| Reclass of warrant liability to additional paid in capital | - | - | - | - | - | - | - | 0 | 0 |
|---|
| Reclass Of Deferred Asset Issuance Of Loan Payable To Debt Discount | - | - | - | - | - | - | - | 0 | 0 |
|---|
| Settlement of liability for exercise of warrants | - | - | - | - | - | - | - | 3 | - |
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