CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($)
$ in Thousands |
12 Months Ended |
Dec. 31, 2018 |
Dec. 31, 2017 |
Dec. 31, 2016 |
| Cash flows from operating activities: |
|
|
|
| Net loss |
$ (89,195)
|
$ (43,847)
|
$ (11,016)
|
| Adjustments to reconcile net loss to net cash used in operating activities: |
|
|
|
| Stock-based compensation expense |
27,528
|
17,903
|
147
|
| Depreciation and amortization expense |
1,263
|
447
|
118
|
| Issuance of common stock for technology license |
|
|
55
|
| Change in fair value of preferred stock warrant liability |
2,187
|
785
|
(1)
|
| Accretion of discount on investments |
(329)
|
|
|
| Loss on disposal of property and equipment |
|
|
29
|
| Non-cash interest expense |
86
|
42
|
27
|
| Changes in operating assets and liabilities: |
|
|
|
| Prepaid expenses and other current assets |
(9,037)
|
(647)
|
(36)
|
| Other assets |
(74)
|
|
|
| Accounts payable |
4,938
|
1,110
|
589
|
| Accrued expenses and other current liabilities |
4,307
|
2,247
|
618
|
| Deferred rent |
(15)
|
22
|
(32)
|
| Net cash used in operating activities |
(58,341)
|
(21,938)
|
(9,502)
|
| Cash flows from investing activities: |
|
|
|
| Purchases of property, plant and equipment |
(14,952)
|
(2,251)
|
(443)
|
| Purchases of investments |
(160,972)
|
|
|
| Sales and maturities of investments |
64,285
|
|
|
| Net cash used in investing activities |
(111,639)
|
(2,251)
|
(443)
|
| Cash flows from financing activities: |
|
|
|
| Proceeds from issuance of convertible preferred stock, net of issuance costs |
100,986
|
120,067
|
11,437
|
| Proceeds from initial public offering of common stock, net of commissions and underwriting discounts |
257,866
|
|
|
| Payments of initial public offering costs |
(3,548)
|
|
|
| Proceeds from issuance of common stock upon exercise of stock options |
64
|
37
|
|
| Proceeds from the sale of restricted common stock |
|
100
|
|
| Proceeds from repayment of promissory note |
246
|
|
|
| Payments of debt issuance costs |
(285)
|
(11)
|
(19)
|
| Proceeds from borrowings under loan and security agreement |
25,000
|
1,500
|
4,000
|
| Payment of long-term debt |
(5,500)
|
|
|
| Net cash provided by financing activities |
374,829
|
121,693
|
15,418
|
| Net increase in cash, cash equivalents and restricted cash |
204,849
|
97,504
|
5,473
|
| Cash, cash equivalents and restricted cash at beginning of period |
104,572
|
7,068
|
1,595
|
| Cash, cash equivalents and restricted cash at end of period |
309,421
|
104,572
|
7,068
|
| Supplemental cash flow information: |
|
|
|
| Cash paid for interest |
385
|
265
|
115
|
| Supplemental disclosure of non-cash investing and financing information: |
|
|
|
| Purchases of property, plant and equipment included in accounts payable or accrued expenses |
1,550
|
9
|
266
|
| Landlord incentives for leasehold improvements recorded as deferred rent |
|
|
100
|
| Amounts capitalized under build-to-suit lease transaction |
45,142
|
|
|
| Debt issuance costs included in accounts payable and accrued expenses |
489
|
|
|
| Issuance of preferred stock warrant in connection with loan and security agreement |
|
14
|
|
| Reclassification of warrants to additional paid-in capital |
3,053
|
|
|
| Accretion of Series A redeemable convertible preferred stock to redemption value |
|
$ 656
|
$ 748
|
| Conversion of preferred stock to common stock upon closing of the initial public offering |
$ 240,776
|
|
|