XML 72 R30.htm IDEA: XBRL DOCUMENT v3.20.1

Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2019

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Summary of Stock-Based Compensation Expense

Total stock-based compensation expense is recognized for stock-based awards granted to employees and non-employees and has been reported in the Company’s consolidated statements of operations and comprehensive loss as follows:

		Year Ended December 31,
		2019				2018				2017
		(In thousands)
Research and development		$	1,542			$	1,236			$	246
General and administrative			2,152				1,557				224
Total stock-based compensation expense		$	3,694			$	2,793			$	470

Summary of Stock Option Activity

The following table summarizes stock option activity under the Plan:

		Shares Available for Grant				Number of Options Outstanding				Weighted- Average Exercise Price per Option ($)				Weighted- Average Remaining Contract Term (Years)				Aggregate Intrinsic Value ($)
		(In thousands)
Outstanding, December 31, 2018			1,350,582				1,122,677				11.63				9.22
Shares reserved for issuance			1,122,213
Options granted			(1,896,527	)			1,896,527				6.28
Restricted stock units granted			(813,335	)
Options exercised			—				(7,029	)			0.79
Options forfeited			449,375				(449,375	)			10.77
Outstanding, December 31, 2019			212,308				2,562,800				7.85				8.84				200
Exercisable, December 31, 2019							461,150				11.40				7.06				37
Vested and expected to vest, December 31, 2019							2,562,800				7.85				8.84				200

Schedule of Assumptions to Estimate Fair Value of Stock Options for Employees and Non-Employees Using Black-Scholes Option Pricing Model

The fair value of stock options for employees and non-employees was estimated using a Black-Scholes option pricing model with the following assumptions:

		Year Ended December 31,
		2019		2018		2017
Employees:
Fair value of common stock		$1.27 - $10.66		$8.57 - $15.45		$0.79 - $9.33
Expected term (in years)		5.5 - 6.1		5.8 - 6.2		5.9 - 6.2
Expected volatility		92.0% - 104.9%		75.9% - 90.6%		74.4% - 74.5%
Risk-free interest rate		1.4% - 2.6%		2.4% - 3.1%		1.9% - 2.2%
Expected dividend yield		0.0%		0.0%		0.0%
Non-employees:
Fair value of common stock		$1.23 - $10.26		$8.62 - $15.45		$0.79 - $10.28
Expected term (in years)		7.4 - 10.0		8.4 - 10.0		9.4 - 10.0
Expected volatility		89.7% - 99.5%		78.0% - 91.2%		74.6% - 77.0%
Risk-free interest rate		1.7% - 2.8%		2.7% - 3.1%		2.3% - 2.4%
Expected dividend yield		0.0%		0.0%		0.0%

Summary of Restricted Stock Activity

The summary of restricted stock activity and related information follows:

		Number of Restricted Shares Outstanding
Unvested shares — December 31, 2018			1,000
Vested			(1,000	)
Unvested shares — December 31, 2019			—

Summary of Restricted Stock Units Activity

The summary of restricted stock unit activity and related information follows:

		Number of Restricted Stock Units Outstanding
Unvested shares — December 31, 2018			24,960
Granted			813,335
Vested			(9,360	)
Unvested shares — December 31, 2019			828,935

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 changes in outstanding nonvested restricted stock 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
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901

+ Details

Name:	us-gaap_NonvestedRestrictedStockSharesActivityTableTextBlock
Namespace Prefix:	us-gaap_
Data Type:	nonnum:textBlockItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Tabular disclosure of cost recognized for award under share-based payment arrangement by plan. Includes, but is not limited to, related tax benefit.

+ 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=116856206&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 changes in outstanding nonvested restricted stock units.

+ 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)(2)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901

+ Details

Name:	us-gaap_ScheduleOfNonvestedRestrictedStockUnitsActivityTableTextBlock
Namespace Prefix:	us-gaap_
Data Type:	nonnum:textBlockItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Tabular disclosure for stock option plans. Includes, but is not limited to, outstanding awards at beginning and end of year, grants, exercises, forfeitures, and weighted-average grant date fair value.

+ 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)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (e)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901

Reference 3: 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)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901

+ Details

Name:	us-gaap_ScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock
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=116856206&loc=d3e5070-113901

+ Details

Name:	us-gaap_ScheduleOfShareBasedPaymentAwardStockOptionsValuationAssumptionsTableTextBlock
Namespace Prefix:	us-gaap_
Data Type:	nonnum:textBlockItemType
Balance Type:	na
Period Type:	duration