CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($)
$ in Thousands |
12 Months Ended |
Dec. 31, 2021 |
Dec. 31, 2020 |
Dec. 31, 2019 |
| Cash flows from operating activities: |
|
|
|
| Net loss |
$ (196,547)
|
$ (167,731)
|
$ (163,458)
|
| Adjustments to reconcile net loss to net cash used in operating activities: |
|
|
|
| Stock-based compensation expense |
35,610
|
33,665
|
41,271
|
| Depreciation and amortization expense |
7,723
|
5,691
|
2,995
|
| Amortization (accretion) of premium (discount) on investments |
118
|
266
|
(2,320)
|
| Loss on disposal of property and equipment |
|
|
335
|
| Non-cash interest expense |
1,280
|
349
|
289
|
| Changes in operating assets and liabilities: |
|
|
|
| Prepaid expenses and other current assets |
1,249
|
992
|
2,655
|
| Operating lease, right-of-use-asset |
5,352
|
5,539
|
4,991
|
| Other assets |
5
|
46
|
2
|
| Accounts payable |
5,858
|
(1,369)
|
(1,037)
|
| Accrued expenses and other current liabilities |
(816)
|
(96)
|
6,107
|
| Other long-term liabilities |
(553)
|
283
|
396
|
| Operating lease liabilities |
(4,401)
|
(5,283)
|
(2,670)
|
| Net cash used in operating activities |
(145,122)
|
(127,648)
|
(110,444)
|
| Cash flows from investing activities: |
|
|
|
| Purchases of property, plant and equipment |
(3,649)
|
(5,497)
|
(40,657)
|
| Purchases of investments |
|
(122,671)
|
(319,133)
|
| Sales and maturities of investments |
85,000
|
228,600
|
227,155
|
| Net cash provided by (used in) investing activities |
81,351
|
100,432
|
(132,635)
|
| Cash flows from financing activities: |
|
|
|
| Proceeds from underwritten public offering of common stock, net of commissions and underwriting discounts |
188,000
|
|
|
| Payments of offering costs |
(360)
|
|
|
| Payments of debt issuance costs |
(150)
|
|
|
| Repurchase of unvested restricted common stock |
|
|
(122)
|
| Proceeds from borrowings under loan and security agreement |
|
25,000
|
25,000
|
| Proceeds from issuance of common stock upon exercise of stock options |
10,963
|
1,484
|
2,413
|
| Net cash provided by financing activities |
198,453
|
26,484
|
27,291
|
| Net increase (decrease) in cash, cash equivalents and restricted cash |
134,682
|
(732)
|
(215,788)
|
| Cash, cash equivalents and restricted cash at beginning of period |
92,901
|
93,633
|
309,421
|
| Cash, cash equivalents and restricted cash at end of period |
227,583
|
92,901
|
93,633
|
| Supplemental cash flow information: |
|
|
|
| Cash paid for interest |
5,092
|
3,822
|
2,961
|
| Cash paid for leases |
7,364
|
8,486
|
5,375
|
| Supplemental disclosure of non-cash investing and financing information: |
|
|
|
| Purchases of property, plant and equipment included in accounts payable or accrued expenses |
1,989
|
317
|
3,095
|
| Offering costs and issuance costs included in accounts payable and accrued expenses |
$ 35
|
|
|
| Lease assets obtained in exchange for new operating lease liabilities |
|
496
|
49,799
|
| Proceeds from issuance of common stock upon exercise of stock options in other current assets |
|
|
$ 32
|
| Lease asset derecognized upon lease cancellation |
|
$ 982
|
|