XML 34 R22.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Stock-Based Compensation (Tables) | 9 Months Ended
--- | ---
Sep. 30, 2018
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract] |
Summary of Stock-Based Compensation Expense | Total stock-based compensation expense related to the Company’s equity incentive plans, 2018 Plan, and 2016 ESPP was as follows (in thousands):
|  | Three Months Ended |  |  | Nine Months Ended |
|  | September 30, |  |  | September 30, |
|  | 2018 |  |  | 2017 |  |  | 2018 |  |  | 2017 |
Research and development |  | $ | 377 |  |  | $ | 277 |  |  | $ | 1,090 |  |  | $ | 672 |
General and administrative |  |  | 695 |  |  |  | 451 |  |  |  | 1,813 |  |  |  | 1,122 |
Total stock-based compensation expense |  | $ | 1,072 |  |  | $ | 728 |  |  | $ | 2,903 |  |  | $ | 1,794 |
Schedule of Estimated Fair Value of Stock Options Granted | The following table summarizes the weighted-average Black-Scholes option pricing model assumptions used to estimate the fair value of stock options granted under the 2016 Plan and 2018 Plan, and the shares purchasable under the 2016 ESPP during the periods presented:
|  | Three Months Ended |  |  | Nine Months Ended |
|  | September 30, |  |  | September 30, |
|  | 2018 |  |  | 2017 |  |  | 2018 |  |  | 2017 |
2016 Plan and 2018 Plan |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Expected term (in years) |  |  | 6.00 |  |  |  | 5.82 |  |  |  | 5.96 |  |  |  | 5.91 |
Expected volatility |  |  | 84 | % |  |  | 85 | % |  |  | 85 | % |  |  | 86 | %
Risk-free interest |  |  | 2.80 | % |  |  | 1.88 | % |  |  | 2.75 | % |  |  | 1.99 | %
Dividend yield |  |  | 0 | % |  |  | 0 | % |  |  | 0 | % |  |  | 0 | %
2016 ESPP |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Expected term (in years) |  |  | 0.50 |  |  |  | 0.50 |  |  |  | 0.49 |  |  |  | 0.50 |
Expected volatility |  |  | 63 | % |  |  | 79 | % |  |  | 66 | % |  |  | 79 | %
Risk-free interest |  |  | 2.45 | % |  |  | 1.23 | % |  |  | 2.20 | % |  |  | 0.90 | %
Dividend yield |  |  | 0 | % |  |  | 0 | % |  |  | 0 | % |  |  | 0 | %

X
- References No definition available. + Details
Name: | us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of the amount of total share-based compensation cost, including the amounts attributable to each share-based compensation plan and any related tax benefits. + 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 (h)(1) -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901 + Details
Name: | us-gaap_ScheduleOfCompensationCostForShareBasedPaymentArrangementsAllocationOfShareBasedCompensationCostsByPlanTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of the significant assumptions used during the year to estimate the fair value of stock options, including, but not limited to: (a) expected term of share options and similar instruments, (b) expected volatility of the entity's shares, (c) expected dividends, (d) risk-free rate(s), and (e) discount for post-vesting restrictions. + 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 (f)(2) -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901 + Details
Name: | us-gaap_ScheduleOfShareBasedPaymentAwardStockOptionsValuationAssumptionsTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration