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Equity-based Compensation and Equity Incentive Plans - Additional Information (Detail) $ / shares in Units, $ in Thousands | 12 Months Ended |  |
--- | --- | --- | ---
Dec. 31, 2019 USD ($) $ / shares shares | Dec. 31, 2018 USD ($) $ / shares shares | Aug. 28, 2017 shares | Aug. 31, 2015 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Exchange ratio of common stock |  |  | 0.5532 |
Weighted average grant date fair value per share of options granted to employees | $ / shares | $ 4.59 | $ 6.35 |  |
Total fair value of awards vested | $ 3,900 | $ 3,300 |  |
Employee unrecognized compensation expense | $ 6,800 |  |  |
Employee unrecognized compensation cost, period of recognition | 2 years 4 months 24 days |  |  |
Equity-based compensation expense | $ 4,134 | 4,317 |  |
Restricted Common Stock |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Total fair value of awards vested | 100 | $ 1,300 |  |
Employee unrecognized compensation expense | $ 1,200 |  |  |
Employee unrecognized compensation cost, period of recognition | 1 year 2 months 12 days |  |  |
Granted | shares | 585,600 | 0 |  |
Equity-based compensation expense | $ 345 | $ 956 |  |
ESPP |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Percentage of discount for employees under ESPP | 15.00% |  |  |
Purchase price as a percentage of fair value under ESPP | 85.00% |  |  |
Plan 2015 |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Number of stock option and stock purchase rights available for grant (in shares) | shares |  |  |  | 647,893
Percentage of shares outstanding | 5.00% |  |  |
2017 Plan |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Number of stock option and stock purchase rights available for grant (in shares) | shares |  |  | 1,753,061 |
2015 and 2017 Plan |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Shares available for future grants | shares | 676,388 |  |  |
Modifications in Equity Awards | Separation of Former Chief Executive Officer |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Equity-based compensation |  | $ 700 |  |

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- Definition Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. + 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 (i) -URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901 + Details
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- Definition Fair value of share-based awards for which the grantee gained the right by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash. + 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 (d)(2) -URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901 + Details
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- Definition The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable. + 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 -URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901 + Details
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