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Equity-based Compensation and Equity Incentive Plans - Schedule of Stock Option Activity Under 2015 and 2017 Plan (Detail) - 2015 and 2017 Plan - USD ($) $ / shares in Units, $ in Thousands | 12 Months Ended
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Dec. 31, 2019 | Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |
Outstanding Beginning balance, Number of options | 1,739,884 |
Granted, Number of options | 1,427,030 |
Cancelled or Forfeited, Number of options | (880,495) |
Outstanding Ending balance, Number of options | 2,286,419 | 1,739,884
Number of options, Vested or expected to vest | 2,286,419 |
Number of options, Exercisable | 845,102 |
Beginning balance, Weighted-average price | $ 11.92 |
Granted, Weighted-average price | 7.07 |
Cancelled or Forfeited, Weighted-average price | 11.02 |
Ending balance, Weighted-average price | 9.24 | $ 11.92
Weighted-average price Vested or expected to vest | 9.24 |
Weighted-average price, Exercisable | $ 11.43 |
Outstanding, weighted average remaining contractual term (Year) | 8 years 8 months 12 days | 9 years
Weighted average remaining contractual term, Vested or expected to vest | 8 years 8 months 12 days |
Weighted average remaining contractual term, Exercisable | 8 years 1 month 6 days |
Cancelled or Forfeited, Aggregate Intrinsic value | $ 25 |
Ending balance, Aggregate Intrinsic value | 43 |
Aggregate Intrinsic value, Vested or expected to vest at December 31, 2019 | $ 43 |

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- Definition The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(1)(iii) -URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901 + Details
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- Definition The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(1)(iii) -URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901 + Details
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- Definition The number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(1)(iv)(3) -URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901 + Details
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