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Stock Based Compensation - Equity Incentive Plan - Additional Information (Detail) - USD ($) |  | 6 Months Ended |  |
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Apr. 30, 2015 | Jun. 30, 2020 | May 26, 2020 | Dec. 28, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Employee contribution through payroll withholdings |  | $ 217,204 |  |
Employee Stock Purchase Plan [Member] |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Share-based compensation arrangement by share-based payment award, number of shares authorized for issuance |  |  | 850,000 |
Common stock, capital shares reserved for future issuance | 600,000 |  | 250,000 |
Common stock remain eligible to be issued |  | 271,380 |  |
Lowest percentage of annual compensation to be utilized by an employee for purchase of shares under the plan | 1.00% |  |  |
Highest percentage of annual compensation to be utilized by an employee for purchase of shares under the plan | 10.00% |  |  |
Maximum number of shares permitted to purchase | 7,500 |  |  |
Offering period | 6 months |  |  |
Exercise price discount from fair value on offering date | 85.00% |  |  |
Exercise price discount from fair value on exercise date | 85.00% | 15.00% |  |
Share-based compensation arrangement by share-based payment award, terms of award |  | In April 2015, the Company’s Board approved the ESPP, under which 600,000 shares of common stock have been reserved for purchase by the Company’s employees, subject to the approval by the stockholders. On May 21, 2015, the Company’s stockholders approved the ESPP. Effective on May 26, 2020, the Company’s stockholders approved the amendment and restatement of the Employee Stock Purchase Plan to increase the number of shares reserved for issuance through equity-based instruments thereunder by 250,000 shares, bring to 850,000 the total number of shares approved for issuance under that plan. Under the ESPP, employees may designate an amount not less than 1% but not more than 10% of their annual compensation for the purchase of Company shares. No more than 7,500 shares may be purchased by an employee under the ESPP during an offering period. An offering period shall be six months in duration commencing on or about January 1 and July 1 of each year. The exercise price of the option will be the lesser of 85% of the fair market of the common stock on the first business day of the offering period and 85% of the fair market value of the common stock on the applicable exercise date. |  |
2013 Equity Incentive Plan [Member] |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Share-based compensation arrangement by share-based payment award, number of shares authorized for issuance |  |  | 7,285,967 |
Common stock, capital shares reserved for future issuance |  |  | 1,200,000 |
Common stock remain eligible to be issued |  | 1,882,783 |  |
Non-Employee Equity Compensation Plan 2014 [Member] |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Common stock remain eligible to be issued |  | 1,072,794 |  |
2015 Performance Share Unit Plan [Member] |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Share-based compensation arrangement by share-based payment award, number of shares authorized for issuance |  |  | 3,410,104 |
Common stock, capital shares reserved for future issuance |  |  | 700,000 |
Common stock remain eligible to be issued |  | 1,498,274 |  |
2017 Equity Inducement Plan [Member] |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Common stock available to be issued |  | 213,776 |  |
2017 Equity Inducement Plan [Member] | Restricted Stock Units (RSUs) [Member] |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Common stock, capital shares reserved for future issuance |  |  |  | 600,000

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- Definition Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the 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 (a)(2) -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901 + Details
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