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CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands | 3 Months Ended
--- | ---
Mar. 31, 2019 | Mar. 31, 2018
Cash flows from operating activities: |  |
Net loss | $ (10,873) | $ (7,367)
Adjustments to reconcile net loss to net cash used in operating activities: |  |
Stock-based compensation expense | 262 | 128
Depreciation expense | 20 | 26
Non-cash lease expense | 119 |
Non-cash interest expense | 153 | 27
Change in fair value of preferred stock warrant liability | 288 | 592
Change in fair value of derivative liability | (183) | 565
Changes in operating assets and liabilities: |  |
Prepaid expenses and other current assets | (595) | 170
Accounts payable | 1,332 | (563)
Accrued expenses | (2,072) | 240
Operating lease liabilities | (201) |
Net cash used in operating activities | (11,750) | (6,182)
Cash flows from investing activities: |  |
Cash and restricted cash acquired in connection with the Merger | 26,406 |
Net cash provided by investing activities | 26,406 |
Cash flows from financing activities: |  |
Proceeds from exercise of stock options | 113 |
Repurchase of Series Seed convertible preferred stock |  | (1,126)
Repayments of borrowings under loan and security agreement |  | (500)
Payments of issuance costs of convertible preferred stock |  | (34)
Net cash provided by (used in) financing activities | 113 | (1,660)
Effect of exchange rate changes on cash, cash equivalents and restricted cash | (21) |
Net increase (decrease) in cash, cash equivalents and restricted cash | 14,748 | (7,842)
Cash, cash equivalents and restricted cash at beginning of period | 8,498 | 27,048
Cash, cash equivalents and restricted cash at end of period | 23,246 | 19,206
Supplemental disclosure of cash flow information: |  |
Cash paid for interest | 243 | $ 146
Supplemental disclosure of non-cash investing and financing activities: |  |
Conversion of convertible preferred stock into common stock | 64,675 |
Conversion of redeemable common stock into common stock | 734 |
Conversion of convertible preferred stock warrants into common stock warrants | 5,235 |
Fair value of net assets acquired in Merger | $ 46,358 |

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