0001564590-20-043418 | 10-Q | XBRL Viewer | Kalvista Pharmaceuticals INC

Document and Entity Information - shares	3 Months Ended
Document and Entity Information - shares	Jul. 31, 2020	Sep. 04, 2020
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jul. 31, 2020
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q1
Trading Symbol	KALV
Entity Registrant Name	KALVISTA PHARMACEUTICALS, INC.
Entity Central Index Key	0001348911
Current Fiscal Year End Date	--04-30
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Shell Company	false
Document Quarterly Report	true
Title of 12(b) Security	Common Stock, $0.001 par value per share
Security Exchange Name	NASDAQ
Document Transition Report	false
Entity File Number	001-36830
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	20-0915291
Entity Address, Address Line One	55 Cambridge Parkway
Entity Address, Address Line Two	Suite 901E
Entity Address, City or Town	Cambridge
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02142
City Area Code	857
Local Phone Number	999-0075
Entity Common Stock, Shares Outstanding		17,907,559

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jul. 31, 2020	Apr. 30, 2020
Current assets:
Cash and cash equivalents	$ 18,014	$ 15,789
Marketable securities	46,317	51,925
Research and development tax credit receivable	12,638	16,527
Prepaid expenses and other current assets	3,256	4,455
Total current assets	80,225	88,696
Property and equipment, net	2,019	2,043
Right of use assets	1,480	1,612
Other assets	178	178
Total assets	83,902	92,529
Current liabilities:
Accounts payable	1,774	1,677
Accrued expenses	6,170	5,455
Lease liability - current portion	513	588
Total current liabilities	8,457	7,720
Long-term liabilities:
Lease liability - net of current portion	1,010	1,057
Total long-term liabilities	1,010	1,057
Commitments and contingencies (Note 5)
Stockholders’ equity
Common stock, $0.001 par value, 100,000,000 authorized Shares issued and outstanding: 17,880,414 at July 31, 2020 and 17,845,599 at April 30, 2020	18	18
Additional paid-in capital	208,442	207,208
Accumulated deficit	(132,406)	(121,592)
Accumulated other comprehensive loss	(1,619)	(1,882)
Total stockholders’ equity	74,435	83,752
Total liabilities and stockholders’ equity	$ 83,902	$ 92,529

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Jul. 31, 2020	Apr. 30, 2020
Statement Of Financial Position [Abstract]
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	17,880,414	17,845,599
Common stock, shares outstanding	17,880,414	17,845,599

Condensed Consolidated Statements of Operations and Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Jul. 31, 2020	Jul. 31, 2019
Income Statement [Abstract]
Revenue		$ 3,369
Operating expenses:
Research and development	$ 11,165	9,686
General and administrative	3,278	3,247
Total operating expenses	14,443	12,933
Operating loss	(14,443)	(9,564)
Other income:
Interest income	259	590
Foreign currency exchange gain (loss)	438	(453)
Other income	2,932	2,089
Total other income	3,629	2,226
Net loss	(10,814)	(7,338)
Other comprehensive income (loss):
Foreign currency translation adjustments	338	(89)
Unrealized holding (loss) gain on marketable securities	(5)	28
Reclassification adjustment for realized (gain) on marketable securities included in net loss	(70)
Other comprehensive income (loss)	263	(61)
Comprehensive loss	$ (10,551)	$ (7,399)
Net loss per share to common stockholders, basic and diluted	$ (0.61)	$ (0.42)
Weighted average common shares outstanding, basic and diluted	17,848,583	17,488,997

Condensed Consolidated Statement of Changes in Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive Loss [Member]
Balance at Apr. 30, 2019	$ 96,738	$ 17	$ 191,123	$ (92,476)	$ (1,926)
Balance, shares at Apr. 30, 2019		17,277,750
Issuance of common stock, net of issuance costs	11,422	$ 1	11,421
Issuance of common stock, net of issuance costs, shares		527,221
Issuance of common stock from equity incentive plans	32		32
Issuance of common stock from equity incentive plans, shares		10,522
Stock-based compensation expense	1,074		1,074
Net loss	(7,338)			(7,338)
Foreign currency translation adjustments	(89)				(89)
Unrealized holding gain (losses) from marketable securities	28
Unrealized holding gains from marketable securities, net of reclassification for realized gains	28				28
Balance at Jul. 31, 2019	101,867	$ 18	203,650	(99,814)	(1,987)
Balance, shares at Jul. 31, 2019		17,815,493
Balance at Apr. 30, 2020	83,752	$ 18	207,208	(121,592)	(1,882)
Balance, shares at Apr. 30, 2020		17,845,599
Issuance of common stock from exercise of stock options	46		46
Issuance of common stock from exercise of stock options, shares		34,815
Stock-based compensation expense	1,188		1,188
Net loss	(10,814)			(10,814)
Foreign currency translation adjustments	338				338
Unrealized holding gain (losses) from marketable securities	(5)				(5)
Reclassification adjustment for realized (gain) on marketable securities included in net loss	(70)				(70)
Balance at Jul. 31, 2020	$ 74,435	$ 18	$ 208,442	$ (132,406)	$ (1,619)
Balance, shares at Jul. 31, 2020		17,880,414

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Jul. 31, 2020	Jul. 31, 2019
Cash flows from operating activities
Net loss	$ (10,814)	$ (7,338)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	128	121
Stock-based compensation expense	1,188	1,074
Realized gain from sale of marketable securities	(70)	(29)
Non-cash operating lease expense	8	1
Amortization of premium on marketable securities	68	35
Foreign currency exchange (gain) loss	(432)	454
Changes in operating assets and liabilities:
Research and development tax credit receivable	4,462	(2,060)
Prepaid expenses and other current assets	1,301	561
Accounts payable	35	392
Accrued expenses	538	(1,117)
Deferred revenue		(3,369)
Net cash used in operating activities	(3,588)	(11,275)
Cash flows from investing activities
Purchases of marketable securities	(9,807)	(19,646)
Sales and maturities of marketable securities	15,342	18,214
Acquisition of property and equipment	(22)	(98)
Net cash provided by (used in) investing activities	5,513	(1,530)
Cash flows from financing activities
Issuance of common stock, net of offering expenses		11,422
Issuance of common stock from equity incentive plans	46	32
Finance lease principal payments		(54)
Net cash provided by financing activities	46	11,400
Effect of exchange rate changes on cash and cash equivalents	254	(494)
Net increase (decrease) in cash and cash equivalents	2,225	(1,899)
Cash and cash equivalents at beginning of period	15,789	32,006
Cash and cash equivalents at end of period	$ 18,014	30,107
Supplemental disclosures of cash flow information:
Acquisition of property and equipment in accounts payable		$ 47

The Company

3 Months Ended

Jul. 31, 2020

Organization Consolidation And Presentation Of Financial Statements [Abstract]

The Company

1.	The Company

Company Background

KalVista Pharmaceuticals, Inc. (“KalVista” or the “Company”) is a clinical stage pharmaceutical company focused on the discovery, development and commercialization of small molecule protease inhibitors for diseases with significant unmet need. The Company’s first product candidates are inhibitors of plasma kallikrein being developed for two indications: hereditary angioedema (“HAE”) and diabetic macular edema (“DME”). The Company applies its insights into the chemistry of proteases and, with current programs, the biology of the plasma kallikrein system, to develop small molecule inhibitors with high selectivity, potency and bioavailability that it believes will make them successful treatments for disease.

KalVista has created a structurally diverse portfolio of oral plasma kallikrein inhibitors and advanced multiple drug candidates into clinical trials in order to create best-in-class oral therapies for both HAE and DME. In HAE, KalVista intends to develop drug candidates for both on-demand and prophylactic use, with the goal of providing patients with a complete set of oral options to treat their disease. KalVista believes that this ability to provide products to meet the full spectrum of patient needs will be an important differentiator from other companies that are only able to address a portion of the market with oral offerings.

KVD900, the Company’s most advanced HAE drug candidate, is being developed as a potential on-demand therapy for HAE attacks. This program is currently in a Phase 2, crossover design, clinical trial intended to evaluate the safety and efficacy of KVD900 compared to placebo in treating HAE attacks. The trial has achieved its target enrollment and is expected to provide data in the fourth quarter of 2020. KVD900 has received Fast Track designation from the U.S. Food and Drug Administration.

KVD824 is KalVista’s next oral candidate, which is being developed as a prophylactic treatment for HAE. Based on preclinical and clinical work conducted, the Company believes that KVD824 can achieve the profile necessary for a twice-daily treatment for prevention of HAE attacks, which also remains an area of high unmet need. The Company continues to undertake additional studies to optimize the formulation and exposure profile, following which the Company expects to submit an Investigational New Drug Application for a Phase 2 clinical trial.

The Company’s most advanced program in DME is KVD001, an intravitreally delivered plasma kallikrein inhibitor which completed a Phase 2 trial in 2019. The Company is currently evaluating its development strategy in this indication and expects to provide further updates when appropriate.

The Company’s headquarters is located in Cambridge, Massachusetts, with research activities located in Porton Down, United Kingdom and Boston, Massachusetts.

COVID-19

As a result of the novel strain of coronavirus, SARS-CoV-2 (“COVID-19”) pandemic, the Company has experienced and may continue to experience constrained supplies of product candidates or, with respect to the Company’s clinical trials, delays in enrollment, site initiation, participant dosing, distribution of clinical trial materials, study monitoring and data analysis, which could materially adversely impact the Company’s business, results of operations and overall financial performance in future periods. Any such delays to the Company’s planned clinical timelines for KVD900 and KVD824 could also impact the use and sufficiency of existing cash reserves, and the Company may be required to raise additional capital earlier than previously planned. The Company may be unable to raise additional capital if and when needed, which may result in further delays or suspension of our development plans. The extent to which COVID-19 may impact the Company’s financial condition, results of operations or cash flows is uncertain and will continue to be monitored closely.

Liquidity

The Company has devoted substantially all of its efforts to research and development, including clinical trials of its product candidates. The Company has not completed the development of any product candidates. Pharmaceutical drug product candidates, like those being developed by the Company, require approvals from the FDA or foreign regulatory agencies prior to commercial sales. There can be no assurance that any product candidates will receive the necessary approvals and any failure to receive approval or delay in approval may have a material adverse impact on the Company’s business and financial results. The Company has not yet commenced commercial operations. The Company is subject to a number of risks and uncertainties similar to those of other life science companies developing new products, including, among others, the risks related to the necessity to obtain adequate additional financing, to successfully develop product candidates, to obtain regulatory approval of product candidates, to comply with government regulations, to successfully commercialize its potential products, to the protection of proprietary technology and to the dependence on key individuals.

The Company has funded operations primarily through the issuance and sale of capital stock and the option agreement with Merck Sharpe & Dohme Corp. entered into in 2017 (the “Merck Option Agreement”). As of July 31, 2020, the Company had an accumulated deficit of $132.4 million and $64.3 million of cash, cash equivalents and marketable securities. To date, the Company has not generated any product sales revenues and does not have any products that have been approved for commercialization. The Company does not expect to generate significant revenue unless and until it obtains regulatory approval for, and commercializes, one of its current or future product candidates. The Company anticipates that it will continue to incur losses for the foreseeable future, and it expects those losses to increase as it continues the development of, and seeks regulatory approvals for, product candidates, and begins to commercialize any approved products. The Company is subject to all of the risks inherent in the development of new therapeutic products, and it may encounter unforeseen expenses, difficulties, complications, delays and other unknown factors that may adversely affect its business. The Company currently anticipates that, based upon its operating plans and existing capital resources, it has sufficient funding to operate for at least the next twelve months.

Until such time, if ever, as the Company can generate substantial revenues, it expects to finance its cash needs through a combination of equity or debt financings, collaborations, strategic partnerships and licensing arrangements. To the extent that additional capital is raised through the sale of stock or convertible debt securities, the ownership interest of existing stockholders may be diluted, and the terms of these newly issued securities may include liquidation or other preferences that adversely affect the rights of common stockholders. Debt financing, if available, may involve agreements that include increased fixed payment obligations and covenants limiting or restricting the Company’s ability to take specific actions, such as incurring additional debt, making capital expenditures, declaring dividends, selling or licensing intellectual property rights and other operating restrictions that could adversely impact its ability to conduct business. Additional fundraising through collaborations, strategic partnerships or licensing arrangements with third parties may require the Company to relinquish valuable rights to product candidates, including other technologies, future revenue streams or research programs, or grant licenses on terms that may not be favorable. If the Company is unable to raise additional funds when needed, it may be required to delay, limit, reduce or terminate product development or future commercialization efforts or grant rights to develop and commercialize other product candidates even if it would otherwise prefer to develop and commercialize such product candidates internally.

Summary of Significant Accounting Policies

3 Months Ended

Jul. 31, 2020

Accounting Policies [Abstract]

Summary of Significant Accounting Policies

2.	Summary of Significant Accounting Policies

Principles of Consolidation: The accompanying unaudited interim condensed consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation.

The accompanying unaudited interim condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) for interim financial information and in accordance with the instructions to Form 10-Q and Rule 10-01 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by generally accepted accounting principles for complete financial statements. Such financial statements reflect all adjustments that are, in management’s opinion, necessary to present fairly, in all material respects, the Company’s consolidated financial position, results of operations, and cash flows. The unaudited interim condensed consolidated financial statements have been prepared on the same basis as the annual financial statements. There were no adjustments other than normal recurring adjustments. These unaudited interim condensed consolidated financial results are not necessarily indicative of the results to be expected for the year ending April 30, 2021, or for any other future annual or interim period. The accompanying unaudited interim condensed consolidated financial statements should be read in conjunction with the audited financial statements as of and for the year ended April 30, 2020 in the Company’s Annual Report on Form 10-K filed with the Securities and Exchange Commission (“SEC”) on July 1, 2020.

Segment Reporting: The chief operating decision maker, the CEO, manages the Company’s operations as a single operating segment for the purposes of assessing performance and making operating decisions.

Net Loss per Share: Basic net loss per share is computed by dividing the net loss by the weighted average number of common shares outstanding during the period. Diluted net loss per share is computed by dividing net loss by the sum of the weighted average number of common shares and the number of potential dilutive common share equivalents outstanding during the period. Potential dilutive common share equivalents consist of the incremental common shares issuable upon the exercise of share options and awards.

Potential dilutive common share equivalents consist of:

	July 31,
	2020		2019
Stock options and awards		2,991,653		2,289,947

In computing diluted earnings per share, common share equivalents are not considered in periods in which a net loss is reported, as the inclusion of the common share equivalents would be anti-dilutive. As a result, there is no difference between the Company’s basic and diluted loss per share for the periods presented.

Fair Value Measurement: The Company classifies fair value measurements using a three level hierarchy that prioritizes the inputs used to measure fair value. This hierarchy requires entities to maximize the use of observable inputs and minimize the use of unobservable inputs. The three levels of inputs used to measure fair value are as follows: Level 1, quoted market prices in active markets for identical assets or liabilities; Level 2, observable inputs other than quoted market prices included in Level 1, such as quoted market prices for markets that are not active or other inputs that are observable or can be corroborated by observable market data; and Level 3, unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities, including certain pricing models, discounted cash flow methodologies and similar techniques that use significant unobservable inputs. These fair values are obtained from independent pricing services which utilize Level 1 and Level 2 inputs.

The following tables summarize the cash equivalents and marketable securities measured at fair value on a recurring basis as of July 31, 2020 and April 30, 2020 (in thousands):

							Balance at
	Level 1		Level 2		Level 3		July 31, 2020
Cash equivalents	$	2,602	$	—	$	—	$	2,602
Marketable securities:
Corporate debt securities		—		34,417		—		34,417
U.S. government agency securities		—		11,900		—		11,900
	$	2,602	$	46,317	$	—	$	48,919

							Balance at
	Level 1		Level 2		Level 3		April 30, 2020
Cash equivalents	$	650	$	—	$	—	$	650
Marketable securities:
Corporate debt securities		—		39,216		—		39,216
U.S. government agency securities		—		12,709		—		12,709
	$	650	$	51,925	$	—	$	52,575

Marketable Securities

3 Months Ended

Jul. 31, 2020

Investments Debt And Equity Securities [Abstract]

Marketable Securities

3.	Marketable Securities

The objectives of the Company’s investment policy are to ensure the safety and preservation of invested funds, as well as to maintain liquidity sufficient to meet cash flow requirements. The Company invests its excess cash in securities issued by financial institutions, commercial companies, and government agencies that management believes to be of high credit quality in order to limit the amount of its credit exposure. The Company has not realized any losses from its investments.

The Company classifies all of its debt securities as available-for-sale. Unrealized gains and losses on investments are recognized in accumulated comprehensive loss, unless an unrealized loss is considered to be other than temporary, in which case the unrealized loss is charged to operations. The Company periodically reviews its investments for other than temporary declines in fair value below cost basis and whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. The Company believes the individual unrealized losses represent temporary declines primarily resulting from interest rate changes. Realized gains and losses are included in other income in the consolidated statements of operations and comprehensive loss and are determined using the specific identification method with transactions recorded on a trade date basis.

The following tables summarize marketable securities held at July 31, 2020 and April 30, 2020 (in thousands):

	July 31, 2020
	Amortized		Unrealized		Unrealized			Estimated
	Cost		Gains		Losses			Fair Value
Corporate debt securities	$	34,154	$	268	$	(5	)	$	34,417
Obligations of the U.S. Government and its agencies		11,770		130		—			11,900
Total	$	45,924	$	398	$	(5	)	$	46,317

	April 30, 2020
	Amortized		Unrealized		Unrealized			Estimated
	Cost		Gains		Losses			Fair Value
Corporate debt securities	$	38,922	$	295	$	(1	)	$	39,216
Obligations of the U.S. Government and its agencies		12,534		175		—			12,709
Total	$	51,456	$	470	$	(1	)	$	51,925

The following table summarizes the scheduled maturity for the Company’s marketable securities at July 31, 2020 (in thousands):

	July 31, 2020
Maturing in one year or less	$	28,895
Maturing after one year through two years		7,570
Maturing after two years		9,852
Total	$	46,317

Accrued Expenses

3 Months Ended

Jul. 31, 2020

Payables And Accruals [Abstract]

Accrued Expenses

4.	Accrued Expenses

Accrued expenses consisted of the following as of July 31, 2020 and April 30, 2020 (in thousands):

	July 31,		April 30,
	2020		2020
Compensation expense	$	2,945	$	2,821
Research expense		2,970		2,333
Professional fees		208		173
Other expenses		47		128
	$	6,170	$	5,455

Commitments and Contingencies

3 Months Ended

Jul. 31, 2020

Commitments And Contingencies Disclosure [Abstract]

Commitments and Contingencies

5.	Commitments and Contingencies

Clinical Studies: The Company enters into contractual agreements with contract research organizations in connection with preclinical and toxicology studies and clinical trials. Amounts due under these agreements are invoiced to the Company on predetermined schedules during the course of the studies and clinical trials and are not refundable regardless of the outcome. The Company has a contractual obligation related to the expected future costs to be incurred to complete the ongoing preclinical studies and clinical trials. The remaining commitments, which have cancellation provisions, total $3.4 million at July 31, 2020.

Indemnification: In the normal course of business, the Company enters into contracts and agreements that contain a variety of representations and warranties and provide for general indemnification. The Company’s exposure under these agreements is unknown because it involves future claims that may be made against the Company but have not yet been made. To date, the Company has not paid any claims or been required to defend any action related to its indemnification obligations. However, the Company may record charges in the future as a result of these indemnification obligations. No amounts associated with such indemnifications have been recorded to date.

Contingencies: From time to time, the Company may have certain contingent liabilities that arise in the ordinary course of business activities. The Company accrues a liability for such matters when it is probable that future expenditures will be made and such expenditures can be reasonably estimated. There were no contingent liabilities requiring accrual at July 31, 2020.

As a result of the terms of grant income received in prior years, upon successful regulatory approval and following the first commercial sale of certain DME products, the Company will be required to pay royalty fees of up to $1.0 million within 90 days of the first commercial sale of the product subject to certain fee caps and follow on payments depending upon commercial success and type of product. Given the stage of development of the current pipeline of products it is not possible to predict with certainty the amount or timing of any such liability.

Leases

3 Months Ended

Jul. 31, 2020

Leases [Abstract]

Leases

The Company has a lease agreement for approximately 2,700 square feet of space for its headquarters located in Cambridge, Massachusetts that commenced in September 2017 for a term of five years.

The Company has lease agreements for approximately 13,400 square feet of office and research laboratory space located in Porton Down, United Kingdom that run through April 2023, with an option to extend through April 2028.

The Company is also party to several operating leases for office and laboratory space as well as certain lab equipment. Total rent expense was $200,000 and $177,000 for the three months ended July 31, 2020 and 2019, respectively and is reflected in general and administrative expenses and research and development expenses as determined by the underlying activities.

The following table summarizes the maturity of undiscounted payments due under lease liabilities and the present value of those liabilities as of July 31, 2020 (in thousands):

Fiscal Years	Operating Leases
2021	$	489
2022		386
2023		242
2024		145
2025		145
Thereafter		447
Total lease payments		1,854
Less: imputed interest		(331	)
Total lease liabilities		1,523
Current lease liabilities		513
Long-term lease liabilities	$	1,010

Summary of Significant Accounting Policies (Policies)

3 Months Ended

Jul. 31, 2020

Accounting Policies [Abstract]

Principles of Consolidation

Segment Reporting

Net Loss per Share

Potential dilutive common share equivalents consist of:

	July 31,
	2020		2019
Stock options and awards		2,991,653		2,289,947

Fair Value Measurement

The following tables summarize the cash equivalents and marketable securities measured at fair value on a recurring basis as of July 31, 2020 and April 30, 2020 (in thousands):

							Balance at
	Level 1		Level 2		Level 3		July 31, 2020
Cash equivalents	$	2,602	$	—	$	—	$	2,602
Marketable securities:
Corporate debt securities		—		34,417		—		34,417
U.S. government agency securities		—		11,900		—		11,900
	$	2,602	$	46,317	$	—	$	48,919

							Balance at
	Level 1		Level 2		Level 3		April 30, 2020
Cash equivalents	$	650	$	—	$	—	$	650
Marketable securities:
Corporate debt securities		—		39,216		—		39,216
U.S. government agency securities		—		12,709		—		12,709
	$	650	$	51,925	$	—	$	52,575

- Definition

Disclosure of accounting policy for segment reporting.

+ References + Details

Summary of Significant Accounting Policies (Tables)

3 Months Ended

Jul. 31, 2020

Accounting Policies [Abstract]

Schedule of Potential Dilutive Common Share Equivalents

Potential dilutive common share equivalents consist of:

	July 31,
	2020		2019
Stock options and awards		2,991,653		2,289,947

Schedule of Cash Equivalents and Marketable Securities Measured at Fair Value

The following tables summarize the cash equivalents and marketable securities measured at fair value on a recurring basis as of July 31, 2020 and April 30, 2020 (in thousands):

							Balance at
	Level 1		Level 2		Level 3		July 31, 2020
Cash equivalents	$	2,602	$	—	$	—	$	2,602
Marketable securities:
Corporate debt securities		—		34,417		—		34,417
U.S. government agency securities		—		11,900		—		11,900
	$	2,602	$	46,317	$	—	$	48,919

							Balance at
	Level 1		Level 2		Level 3		April 30, 2020
Cash equivalents	$	650	$	—	$	—	$	650
Marketable securities:
Corporate debt securities		—		39,216		—		39,216
U.S. government agency securities		—		12,709		—		12,709
	$	650	$	51,925	$	—	$	52,575

Marketable Securities (Tables)

3 Months Ended

Jul. 31, 2020

Investments Debt And Equity Securities [Abstract]

Summary of Marketable Securities Held

The following tables summarize marketable securities held at July 31, 2020 and April 30, 2020 (in thousands):

	July 31, 2020
	Amortized		Unrealized		Unrealized			Estimated
	Cost		Gains		Losses			Fair Value
Corporate debt securities	$	34,154	$	268	$	(5	)	$	34,417
Obligations of the U.S. Government and its agencies		11,770		130		—			11,900
Total	$	45,924	$	398	$	(5	)	$	46,317

	April 30, 2020
	Amortized		Unrealized		Unrealized			Estimated
	Cost		Gains		Losses			Fair Value
Corporate debt securities	$	38,922	$	295	$	(1	)	$	39,216
Obligations of the U.S. Government and its agencies		12,534		175		—			12,709
Total	$	51,456	$	470	$	(1	)	$	51,925

Summary of Scheduled Maturity for Marketable Securities

The following table summarizes the scheduled maturity for the Company’s marketable securities at July 31, 2020 (in thousands):

	July 31, 2020
Maturing in one year or less	$	28,895
Maturing after one year through two years		7,570
Maturing after two years		9,852
Total	$	46,317

Accrued Expenses (Tables)

3 Months Ended

Jul. 31, 2020

Payables And Accruals [Abstract]

Schedule of Accrued Expenses

Accrued expenses consisted of the following as of July 31, 2020 and April 30, 2020 (in thousands):

	July 31,		April 30,
	2020		2020
Compensation expense	$	2,945	$	2,821
Research expense		2,970		2,333
Professional fees		208		173
Other expenses		47		128
	$	6,170	$	5,455

Leases (Tables)

3 Months Ended

Jul. 31, 2020

Leases [Abstract]

Summary of Maturity of Undiscounted Payments and Future Minimum Payments Due Under Lease Liabilities and Present Value of Liabilities

The following table summarizes the maturity of undiscounted payments due under lease liabilities and the present value of those liabilities as of July 31, 2020 (in thousands):

Fiscal Years	Operating Leases
2021	$	489
2022		386
2023		242
2024		145
2025		145
Thereafter		447
Total lease payments		1,854
Less: imputed interest		(331	)
Total lease liabilities		1,523
Current lease liabilities		513
Long-term lease liabilities	$	1,010

The Company - Additional Information (Detail) - USD ($) $ in Thousands	Jul. 31, 2020	Apr. 30, 2020
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Accumulated deficit	$ 132,406	$ 121,592
Cash, cash equivalents and marketable securities	$ 64,300

Summary of Significant Accounting Policies - Schedule of Potential Dilutive Common Share Equivalents (Detail) - shares	3 Months Ended
	Jul. 31, 2020	Jul. 31, 2019
Stock Options and Awards [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Number of anti-dilutive potential common share equivalents outstanding	2,991,653	2,289,947

Summary of Significant Accounting Policies - Schedule of Cash Equivalents and Marketable Securities Measured at Fair Value (Detail) - USD ($) $ in Thousands	Jul. 31, 2020	Apr. 30, 2020
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents	$ 2,602	$ 650
Cash equivalents and marketable securities	48,919	52,575
Level 1 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents	2,602	650
Cash equivalents and marketable securities	2,602	650
Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents and marketable securities	46,317	51,925
Corporate Debt Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities	34,417	39,216
Corporate Debt Securities [Member] \| Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities	34,417	39,216
U.S. Government Agency Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities	11,900	12,709
U.S. Government Agency Securities [Member] \| Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities	$ 11,900	$ 12,709

Marketable Securities - Summary of Marketable Securities Held (Detail) - USD ($) $ in Thousands	Jul. 31, 2020	Apr. 30, 2020
Marketable Securities [Line Items]
Amortized Cost	$ 45,924	$ 51,456
Unrealized Gains	398	470
Unrealized Losses	(5)	(1)
Estimated Fair Value	46,317	51,925
Corporate Debt Securities [Member]
Marketable Securities [Line Items]
Amortized Cost	34,154	38,922
Unrealized Gains	268	295
Unrealized Losses	(5)	(1)
Estimated Fair Value	34,417	39,216
Obligations of U.S. Government and Its Agencies [Member]
Marketable Securities [Line Items]
Amortized Cost	11,770	12,534
Unrealized Gains	130	175
Estimated Fair Value	$ 11,900	$ 12,709

Marketable Securities - Summary of Scheduled Maturity for Marketable Securities (Detail) - USD ($) $ in Thousands	Jul. 31, 2020	Apr. 30, 2020
Investments Debt And Equity Securities [Abstract]
Maturing in one year or less	$ 28,895
Maturing after one year through two years	7,570
Maturing after two years	9,852
Total	$ 46,317	$ 51,925

Accrued Expenses - Schedule of Accrued Expenses (Detail) - USD ($) $ in Thousands	Jul. 31, 2020	Apr. 30, 2020
Payables And Accruals [Abstract]
Compensation expense	$ 2,945	$ 2,821
Research expense	2,970	2,333
Professional fees	208	173
Other expenses	47	128
Total accrued expenses	$ 6,170	$ 5,455

Commitments and Contingencies - Additional Information (Detail)	3 Months Ended
	Jul. 31, 2020 USD ($)
Other Commitments [Line Items]
Contractual obligation remaining commitments including cancellation provisions	$ 3,400,000
Amounts associated with indemnifications	0
Maximum [Member]
Other Commitments [Line Items]
Royalty payable upon completion of first commercial sale of DME	$ 1,000,000
Royalty payment obligations expiration period	90 days
Indemnification Guarantee [Member]
Other Commitments [Line Items]
Contingent liabilities	$ 0

Leases - Additional Information (Detail)	3 Months Ended
Leases - Additional Information (Detail)	Jul. 31, 2020 USD ($) ft²	Jul. 31, 2019 USD ($)
General and Administrative Expenses and Research and Development Expenses [Member]
Lessee Lease Description [Line Items]
Rent expense \| $	$ 200,000	$ 177,000
Massachusetts [Member]
Lessee Lease Description [Line Items]
Lease agreement square feet	2,700
Lessee, lease term	5 years
United Kingdom [Member]
Lessee Lease Description [Line Items]
Lease agreement square feet	13,400
Lease description option to extend	option to extend through April 2028

Leases - Summary of Maturity of Undiscounted Payments Due Under Lease Liabilities and Present Value of Liabilities (Detail) - USD ($) $ in Thousands	Jul. 31, 2020	Apr. 30, 2020
Operating Lease Liabilities Payments Due [Abstract]
2021	$ 489
2022	386
2023	242
2024	145
2025	145
Thereafter	447
Total lease payments	1,854
Less: imputed interest	(331)
Total lease liabilities	1,523
Current lease liabilities	513	$ 588
Long-term lease liabilities	$ 1,010	$ 1,057