Condensed Consolidated Statements of Changes in Stockholders' Equity (Unaudited) - USD ($) shares in Thousands, $ in Thousands |
Total |
Cumulative Effect, Period of Adoption, Adjustment |
Cumulative Effect, Period of Adoption, Adjusted Balance |
At The Market Offering |
Common Stock |
Common Stock
Cumulative Effect, Period of Adoption, Adjusted Balance
|
Common Stock
At The Market Offering
|
Additional Paid-in Capital |
Additional Paid-in Capital
Cumulative Effect, Period of Adoption, Adjusted Balance
|
Additional Paid-in Capital
At The Market Offering
|
Accumulated Other Comprehensive (Loss) Income |
Accumulated Other Comprehensive (Loss) Income
Cumulative Effect, Period of Adoption, Adjusted Balance
|
Accumulated Deficit |
Accumulated Deficit
Cumulative Effect, Period of Adoption, Adjustment
|
Accumulated Deficit
Cumulative Effect, Period of Adoption, Adjusted Balance
|
Beginning balance at Dec. 31, 2018 |
$ 338,857
|
$ 364
|
$ 339,221
|
|
$ 5
|
$ 5
|
|
$ 866,541
|
$ 866,541
|
|
$ (340)
|
$ (340)
|
$ (527,349)
|
$ 364
|
$ (526,985)
|
Beginning balance (in shares) at Dec. 31, 2018 |
|
|
|
|
45,951
|
45,951
|
|
|
|
|
|
|
|
|
|
Accounting Standards Update [Extensible List] |
us-gaap:AccountingStandardsUpdate201602Member
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
RSU settlements, net of shares withheld |
$ (4,575)
|
|
|
|
|
|
|
(4,575)
|
|
|
|
|
|
|
|
RSU settlements, net of shares withheld, shares |
|
|
|
|
197
|
|
|
|
|
|
|
|
|
|
|
Issuance of common stock pursuant to employee stock awards |
2,898
|
|
|
|
|
|
|
2,898
|
|
|
|
|
|
|
|
Issuance of common stock pursuant to employee stock awards, shares |
|
|
|
|
159
|
|
|
|
|
|
|
|
|
|
|
Stock-based compensation expense |
12,269
|
|
|
|
|
|
|
12,269
|
|
|
|
|
|
|
|
Net loss |
(66,257)
|
|
|
|
|
|
|
|
|
|
|
|
(66,257)
|
|
|
Unrealized (loss) gain on available-for-sale securities |
378
|
|
|
|
|
|
|
|
|
|
378
|
|
|
|
|
Ending balance at Mar. 31, 2019 |
283,934
|
|
|
|
$ 5
|
|
|
877,133
|
|
|
38
|
|
(593,242)
|
|
|
Ending balance (in shares) at Mar. 31, 2019 |
|
|
|
|
46,307
|
|
|
|
|
|
|
|
|
|
|
Beginning balance at Dec. 31, 2018 |
338,857
|
$ 364
|
$ 339,221
|
|
$ 5
|
$ 5
|
|
866,541
|
$ 866,541
|
|
(340)
|
$ (340)
|
(527,349)
|
$ 364
|
$ (526,985)
|
Beginning balance (in shares) at Dec. 31, 2018 |
|
|
|
|
45,951
|
45,951
|
|
|
|
|
|
|
|
|
|
Net loss |
(212,480)
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Unrealized (loss) gain on available-for-sale securities |
573
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Ending balance at Sep. 30, 2019 |
318,442
|
|
|
|
$ 5
|
|
|
1,057,669
|
|
|
233
|
|
(739,465)
|
|
|
Ending balance (in shares) at Sep. 30, 2019 |
|
|
|
|
54,125
|
|
|
|
|
|
|
|
|
|
|
Beginning balance at Mar. 31, 2019 |
283,934
|
|
|
|
$ 5
|
|
|
877,133
|
|
|
38
|
|
(593,242)
|
|
|
Beginning balance (in shares) at Mar. 31, 2019 |
|
|
|
|
46,307
|
|
|
|
|
|
|
|
|
|
|
Issuance of common stock, net of commissions and offering costs, value |
7,630
|
|
|
|
|
|
|
7,630
|
|
|
|
|
|
|
|
Issuance of common stock, net of commissions and offering costs, shares |
|
|
|
|
359
|
|
|
|
|
|
|
|
|
|
|
RSU settlements, net of shares withheld |
(2,095)
|
|
|
|
|
|
|
(2,095)
|
|
|
|
|
|
|
|
RSU settlements, net of shares withheld, shares |
|
|
|
|
120
|
|
|
|
|
|
|
|
|
|
|
Issuance of common stock pursuant to employee stock awards |
1,802
|
|
|
|
|
|
|
1,802
|
|
|
|
|
|
|
|
Issuance of common stock pursuant to employee stock awards, shares |
|
|
|
|
97
|
|
|
|
|
|
|
|
|
|
|
Stock-based compensation expense |
15,201
|
|
|
|
|
|
|
15,201
|
|
|
|
|
|
|
|
Net loss |
(74,328)
|
|
|
|
|
|
|
|
|
|
|
|
(74,328)
|
|
|
Unrealized (loss) gain on available-for-sale securities |
135
|
|
|
|
|
|
|
|
|
|
135
|
|
|
|
|
Ending balance at Jun. 30, 2019 |
232,279
|
|
|
|
$ 5
|
|
|
899,671
|
|
|
173
|
|
(667,570)
|
|
|
Ending balance (in shares) at Jun. 30, 2019 |
|
|
|
|
46,883
|
|
|
|
|
|
|
|
|
|
|
Issuance of common stock and pre-funded warrants through underwritten offering, net of offering costs |
140,711
|
|
|
|
|
|
|
140,711
|
|
|
|
|
|
|
|
Issuance of common stock and pre-funded warrants, net of offering costs, shares |
|
|
|
|
6,872
|
|
|
|
|
|
|
|
|
|
|
Issuance of common stock, net of commissions and offering costs, value |
|
|
|
$ 5,000
|
|
|
|
|
|
$ 5,000
|
|
|
|
|
|
Issuance of common stock, net of commissions and offering costs, shares |
|
|
|
|
|
|
327
|
|
|
|
|
|
|
|
|
RSU settlements, net of shares withheld |
(25)
|
|
|
|
|
|
|
(25)
|
|
|
|
|
|
|
|
RSU settlements, net of shares withheld, shares |
|
|
|
|
32
|
|
|
|
|
|
|
|
|
|
|
Issuance of common stock pursuant to employee stock awards |
160
|
|
|
|
|
|
|
160
|
|
|
|
|
|
|
|
Issuance of common stock pursuant to employee stock awards, shares |
|
|
|
|
11
|
|
|
|
|
|
|
|
|
|
|
Stock-based compensation expense |
12,152
|
|
|
|
|
|
|
12,152
|
|
|
|
|
|
|
|
Net loss |
(71,895)
|
|
|
|
|
|
|
|
|
|
|
|
(71,895)
|
|
|
Unrealized (loss) gain on available-for-sale securities |
60
|
|
|
|
|
|
|
|
|
|
60
|
|
|
|
|
Ending balance at Sep. 30, 2019 |
318,442
|
|
|
|
$ 5
|
|
|
1,057,669
|
|
|
233
|
|
(739,465)
|
|
|
Ending balance (in shares) at Sep. 30, 2019 |
|
|
|
|
54,125
|
|
|
|
|
|
|
|
|
|
|
Beginning balance at Dec. 31, 2019 |
290,781
|
|
|
|
$ 6
|
|
|
1,108,516
|
|
|
220
|
|
(817,961)
|
|
|
Beginning balance (in shares) at Dec. 31, 2019 |
|
|
|
|
56,806
|
|
|
|
|
|
|
|
|
|
|
Issuance of common stock, net of commissions and offering costs, value |
|
|
|
22,987
|
|
|
|
|
|
22,987
|
|
|
|
|
|
Issuance of common stock, net of commissions and offering costs, shares |
|
|
|
|
|
|
1,528
|
|
|
|
|
|
|
|
|
Exercise of pre-funded warrants, shares |
|
|
|
|
57
|
|
|
|
|
|
|
|
|
|
|
RSU settlements, net of shares withheld |
(1,395)
|
|
|
|
|
|
|
(1,395)
|
|
|
|
|
|
|
|
RSU settlements, net of shares withheld, shares |
|
|
|
|
455
|
|
|
|
|
|
|
|
|
|
|
Issuance of common stock pursuant to employee stock awards |
1,330
|
|
|
|
|
|
|
1,330
|
|
|
|
|
|
|
|
Issuance of common stock pursuant to employee stock awards, shares |
|
|
|
|
94
|
|
|
|
|
|
|
|
|
|
|
Stock-based compensation expense |
12,644
|
|
|
|
|
|
|
12,644
|
|
|
|
|
|
|
|
Net loss |
(73,509)
|
|
|
|
|
|
|
|
|
|
|
|
(73,509)
|
|
|
Unrealized (loss) gain on available-for-sale securities |
(16)
|
|
|
|
|
|
|
|
|
|
(16)
|
|
|
|
|
Ending balance at Mar. 31, 2020 |
252,822
|
|
|
|
$ 6
|
|
|
1,144,082
|
|
|
204
|
|
(891,470)
|
|
|
Ending balance (in shares) at Mar. 31, 2020 |
|
|
|
|
58,940
|
|
|
|
|
|
|
|
|
|
|
Beginning balance at Dec. 31, 2019 |
290,781
|
|
|
|
$ 6
|
|
|
1,108,516
|
|
|
220
|
|
(817,961)
|
|
|
Beginning balance (in shares) at Dec. 31, 2019 |
|
|
|
|
56,806
|
|
|
|
|
|
|
|
|
|
|
Net loss |
(225,313)
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Unrealized (loss) gain on available-for-sale securities |
307
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Ending balance at Sep. 30, 2020 |
353,935
|
|
|
|
$ 8
|
|
|
1,396,674
|
|
|
527
|
|
(1,043,274)
|
|
|
Ending balance (in shares) at Sep. 30, 2020 |
|
|
|
|
77,220
|
|
|
|
|
|
|
|
|
|
|
Beginning balance at Mar. 31, 2020 |
252,822
|
|
|
|
$ 6
|
|
|
1,144,082
|
|
|
204
|
|
(891,470)
|
|
|
Beginning balance (in shares) at Mar. 31, 2020 |
|
|
|
|
58,940
|
|
|
|
|
|
|
|
|
|
|
Issuance of common stock and pre-funded warrants through underwritten offering, net of offering costs |
189,301
|
|
|
|
$ 1
|
|
|
189,300
|
|
|
|
|
|
|
|
Issuance of common stock and pre-funded warrants, net of offering costs, shares |
|
|
|
|
14,958
|
|
|
|
|
|
|
|
|
|
|
RSU settlements, net of shares withheld, shares |
|
|
|
|
219
|
|
|
|
|
|
|
|
|
|
|
Issuance of common stock pursuant to employee stock awards |
1,904
|
|
|
|
|
|
|
1,904
|
|
|
|
|
|
|
|
Issuance of common stock pursuant to employee stock awards, shares |
|
|
|
|
191
|
|
|
|
|
|
|
|
|
|
|
Stock-based compensation expense |
13,948
|
|
|
|
|
|
|
13,948
|
|
|
|
|
|
|
|
Net loss |
(77,456)
|
|
|
|
|
|
|
|
|
|
|
|
(77,456)
|
|
|
Unrealized (loss) gain on available-for-sale securities |
606
|
|
|
|
|
|
|
|
|
|
606
|
|
|
|
|
Ending balance at Jun. 30, 2020 |
381,125
|
|
|
|
$ 7
|
|
|
1,349,234
|
|
|
810
|
|
(968,926)
|
|
|
Ending balance (in shares) at Jun. 30, 2020 |
|
|
|
|
74,308
|
|
|
|
|
|
|
|
|
|
|
Issuance of common stock, net of commissions and offering costs, value |
|
|
|
$ 34,127
|
|
|
$ 1
|
|
|
$ 34,126
|
|
|
|
|
|
Issuance of common stock, net of commissions and offering costs, shares |
|
|
|
|
|
|
2,582
|
|
|
|
|
|
|
|
|
RSU settlements, net of shares withheld |
(126)
|
|
|
|
|
|
|
(126)
|
|
|
|
|
|
|
|
RSU settlements, net of shares withheld, shares |
|
|
|
|
316
|
|
|
|
|
|
|
|
|
|
|
Issuance of common stock pursuant to employee stock awards |
185
|
|
|
|
|
|
|
185
|
|
|
|
|
|
|
|
Issuance of common stock pursuant to employee stock awards, shares |
|
|
|
|
14
|
|
|
|
|
|
|
|
|
|
|
Stock-based compensation expense |
13,255
|
|
|
|
|
|
|
13,255
|
|
|
|
|
|
|
|
Net loss |
(74,348)
|
|
|
|
|
|
|
|
|
|
|
|
(74,348)
|
|
|
Unrealized (loss) gain on available-for-sale securities |
(283)
|
|
|
|
|
|
|
|
|
|
(283)
|
|
|
|
|
Ending balance at Sep. 30, 2020 |
$ 353,935
|
|
|
|
$ 8
|
|
|
$ 1,396,674
|
|
|
$ 527
|
|
$ (1,043,274)
|
|
|
Ending balance (in shares) at Sep. 30, 2020 |
|
|
|
|
77,220
|
|
|
|
|
|
|
|
|
|
|