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Stock-Based Compensation Plans - Employee Stock Purchase Plan - Additional Information (Detail) - USD ($) | 12 Months Ended |
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Dec. 31, 2019 | Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |
Common stock shares available for issuance | 5,255,735 |
Unrecognized stock-based compensation expense | $ 22,014,000 |
Unrecognized stock-based compensation expenses recognition period | 3 years 5 months 23 days |
Employee Stock Purchase Plan [Member] |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |
ESPP offering period description | The offering periods generally start on the first trading day on or after May 15 and November 15 of each year. |
Length of purchase intervals | 6 months |
ESPP discount rate | 10.00% |
Common stock reserved and available for issuance | 366,667 |
Common stock shares available for issuance | 204,473 | 225,894
Unrecognized stock-based compensation expense | $ 69,000 |
Unrecognized stock-based compensation expenses recognition period | 4 months 13 days |
Employee Stock Purchase Plan - Annual Available for Issuance Share Increase [Member] |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |
Common stock available for future issuance authorized annual share increase | 366,667 |
Common stock available for future issuance authorized annual percentage increase | 1.00% |
ESPP description | The ESPP provides for annual increases in the number of shares available for issuance under the ESPP, equal to the least of (i) 366,667 shares, (ii) 1% of the outstanding shares on such date, or (iii) an amount determined by the compensation committee of the board of directors. |

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- Definition Employee Stock Purchase Plan, description. + References No definition available. + Details
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- Definition Employee Stock Purchase Plan Offering Period Description + References No definition available. + Details
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- Definition Annual share increase in share reserve allowed under the 2013 Plan. + References No definition available. + Details
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- Definition Represents the length of purchase intervals. + References No definition available. + Details
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- Definition Percentage of available share increase in share reserve allowed under the 2013 Equity and 2013 ESPP plans, calculated as a percentage of outstanding shares. + References No definition available. + Details
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- Definition Amount of cost not yet recognized for nonvested award under share-based payment arrangement. + 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 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 Discount rate from fair value on purchase date that participants pay for shares. + 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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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
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- Definition Number of shares authorized for issuance under share-based payment arrangement. + 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 (a)(3) -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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- Details
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