Stockholders' equity	12 Months Ended
Mar. 31, 2021
Stockholders' equity
Stockholders' equity	8. Stockholders’ Equity Common stock As of March 31, 2021 and 2020, the Company’s certificate of incorporation, as amended and restated, authorized the Company to issue up to 150,000,000 shares of common stock, par value $0.001 per share. As of March 31, 2021 and 2020, the Company had reserved 14,572,115 and 10,449,033 shares of common stock for the exercise of outstanding stock options and the vesting of restricted share units, the number of shares remaining available for grant under the Company’s 2018 Omnibus Incentive Compensation Plan and the Company’s Employee Stock Purchase Plan (see Note 9) and the exercise of the outstanding warrants to purchase shares of common, respectively. Undesignated preferred stock As of March 31, 2021, the Company’s certificate of incorporation, as amended and restated, authorized the Company to issue up to 10,000,000 shares of undesignated preferred stock, par value $0.001 per share. There were no undesignated preferred shares issued or outstanding as of March 31, 2021. ATM program In August 2019, the Company entered into a Sales Agreement (as amended, the "Sales Agreement") with SVB Leerink LLC (the "Agent"), pursuant to which the Company could sell, from time to time, at its option, up to an aggregate amount of $75,000 of shares of the Company's common stock, $0.001 par value per share through the Agent, as the Company's sales agent. In June 2020, the 2019 Sales Agreement was amended to reduce the aggregate offering amount under the 2019 Sales Agreement from $75,000 of shares to $30,000 of shares. On August 11, 2020, the 2019 Sales Agreement was terminated by the execution by the Company and the Agent of a new sales agreement, which was subsequently amended on October 21, 2020 (as amended, the “2020 Sales Agreement”). Under the 2020 Sales Agreement the Company may sell, from time to time, at its option, up to an aggregate of $62,500 of shares of the Company’s common stock, $0.001 par value per share (the “Shares”), through the Agent, as the Company’s sales agent. Any Shares to be offered and sold under the 2020 Sales Agreement will be issued and sold (i) by methods deemed to be an "at the market offering" ("ATM"), as defined in Rule 415(a)(4) promulgated under the Securities Act of 1933, as amended or in negotiated transactions, if authorized by the Company, and (ii) pursuant to, and only upon the effectiveness of, a registration statement on Form S-3 filed by the Company with the Securities and Exchange Commission on August 11, 2020 for an offering of up to $350,000 of various securities, including shares of the Company’s common stock, preferred stock, debt securities, warrants and/or units for sale to the public in one or more public offerings. Subject to the terms of the 2020 Sales Agreement, the Agent will use reasonable efforts to sell the Shares from time to time, based upon the Company’s instructions (including any price, time or size limits or other customary parameters or conditions the Company may impose). The Company cannot provide any assurances that it will issue any Shares pursuant to the 2020 Sales Agreement. The Company will pay the Agent a commission of up to 3.0% of the gross proceeds from the sale of the Shares, if any. The Company has also agreed to provide the Agent with customary indemnification rights. During the year ended March 31, 2020, the Company issued and sold 287,559 shares, respectively, of common stock under the 2019 Sales Agreement, for gross proceeds of $4,568 less offering fees of $137 for net proceeds of $4,431 under the ATM . The Company did not issue or sell any shares under the 2020 Sales Agreement during the year ended March 31, 2021. Equity offerings In November 2019, pursuant to an underwriting agreement (the “November 2019 Underwriting Agreement”) with J.P. Morgan Securities LLC and SVB Leerink LLC, as representatives of the several underwriters named therein (the “November 2019 Underwriters”), the Company issued and sold to the November 2019 Underwriters (a) 4,516,561 shares of the Company’s common stock (the “November 2019 Shares”), inclusive of the November 2019 Underwriters partially exercised 30-day option and purchased an additional 838,530 shares of the Company’s common stock, and (b) pre-funded warrants to purchase 2,200,000 shares of the Company’s common stock (the “November 2019 Pre-Funded Warrants”). The November 2019 shares were sold to the November 2019 Underwriters (the “November 2019 Offering”) at the public offering price of $13.61 per share and the pre-funded warrants were sold at a public offering price of $13.6099 per November 2019 Pre-Funded Warrant, which represented the per share public offering price for November 2019 Shares less a $0.0001 per share exercise price for each such November 2019 Pre-funded Warrant. The Company received aggregate net proceeds of approximately $85,598 in the November 2019 Offering, after deducting underwriting discounts, commissions and other offering expenses payable by the Company of approximately $5,814. Funds affiliated with Redmile Group, LLC purchased all of the November 2019 Pre-Funded Warrants. The November 2019 Pre-Funded Warrants are exercisable at any time after the date of issuance. A holder of November 2019 Pre-Funded Warrants may not exercise the November 2019 Pre-Funded Warrant if the holder, together with its affiliates, would beneficially own more than 9.99% of the number of shares of the Company’s common stock outstanding immediately after giving effect to such exercise. In June 2020, pursuant to an underwriting agreement (the “June 2020 Underwriting Agreement”) with J.P. Morgan Securities LLC and SVB Leerink LLC, as representatives of the several underwriters named therein (“the June 2020 Underwriters”), the Company sold to the June 2020 Underwriters (a) 3,478,261 shares of the Company’s common stock (the “June 2020 Shares”), inclusive of the underwrites 30-day option to purchase up to an additional 652,173 shares of the Company’s commons stock, and (b) pre-funded warrants to purchase 1,521,738 shares of the Company’s common stock (the “June 2020 Pre-Funded Warrants”).The June 2020 Shares of the Company’s common stock were sold to the June 2020 Underwriters at the public offering price of $23.00 per share and the June 2020 Pre-Funded Warrants were sold at a public offering price of $22.9999 per June 2020 Pre-Funded Warrant, which represented the per share public offering price for the June 2020 shares less a $0.0001 per share exercise price for each such June 2020 Pre-Funded Warrant. The Company received aggregate net proceeds of approximately $107,782 after deducting underwriting discounts, commissions and other offering expenses payable by the Company of approximately $7,217. Funds affiliated with Redmile Group, LLC and funds affiliated with a second institutional investor purchased all of the June 2020 Pre-Funded Warrants. The June 2020 Pre-Funded Warrants are exercisable at any time after the date of issuance. A holder of June 2020 Pre-Funded Warrants may not exercise the June 2020 Pre-Funded Warrants if the holder, together with its affiliates, would beneficially own more than 9.99% of the number of shares of the Company’s common stock outstanding immediately after giving effect to such exercise. A holder of June 2020 Pre-Funded Warrants may increase or decrease this percentage up to 19.99% by providing at least 61 days’ prior notice to the Company. In October 2020, pursuant to an underwriting agreement with J.P. Morgan Securities LLC and SVB Leerink LLC, as representatives of the several underwriters named therein, the Company issued and sold to the underwriters (a) 5,625,000 shares of the Company’s common stock, inclusive of the underwriters 30-day option to purchase up to an additional 937,500 shares of the Company’s common stock, and (b) pre-funded warrants to purchase 1,562,500 shares of the Company’s common stock (the “October 2020 Pre-Funded Warrants”). The shares of the Company’s common stock were sold to the underwriters at the public offering price of $40.00 per share and the pre-funded warrants were sold at a public offering price of $39.9999 per October 2020 Pre-Funded Warrant, which represented the per share public offering price for the Company’s common stock less a $0.0001 per share exercise price for each such pre-funded warrant. The Company received aggregate net proceeds of approximately $269,975 after deducting underwriting discounts, commissions and other offering expenses payable by the Company of approximately $17,525. Funds affiliated with Redmile Group, LLC and funds affiliated with a second institutional investor purchased all of the October 2020 Pre-Funded Warrants. The October 2020 Pre-Funded Warrants are exercisable at any time after the date of issuance. A holder of October 2020 Pre-Funded Warrants may not exercise the October 2020 Pre-Funded Warrants if the holder, together with its affiliates, would beneficially own more than 9.99% of the number of shares of the Company’s common stock outstanding immediately after giving effect to such exercise. A holder of October 2020 Pre-Funded Warrants may increase or decrease this percentage up to 19.99% by providing at least 61 days’ prior notice to the Company. Other than as set forth in Note 10 to these consolidated financial statements, including in the calculation of basic and diluted net loss per share attributable to common stockholders, the 5,284,238 shares of the Company’s common stock into which the November 2019 Pre-Funded Warrants, the June 2020 Pre-Funded Warrants and October 2020 Pre-Funded Warrants are exercisable are not included in the number of issued and outstanding shares of the Company’s common stock set forth herein. As of March 31, 2021, none of the November 2019 Pre-Funded Warrants, the June 2020 Pre-Funded Warrants, or the October 2020 Pre-Funded Warrants had been exercised.

8. Stockholders’ Equity

Common stock

As of March 31, 2021 and 2020, the Company’s certificate of incorporation, as amended and restated, authorized the Company to issue up to 150,000,000 shares of common stock, par value $0.001 per share.

As of March 31, 2021 and 2020, the Company had reserved 14,572,115 and 10,449,033 shares of common stock for the exercise of outstanding stock options and the vesting of restricted share units, the number of shares remaining available for grant under the Company’s 2018 Omnibus Incentive Compensation Plan and the Company’s Employee Stock Purchase Plan (see Note 9) and the exercise of the outstanding warrants to purchase shares of common, respectively.

Undesignated preferred stock

As of March 31, 2021, the Company’s certificate of incorporation, as amended and restated, authorized the Company to issue up to 10,000,000 shares of undesignated preferred stock, par value $0.001 per share. There were no undesignated preferred shares issued or outstanding as of March 31, 2021.

ATM program

In August 2019, the Company entered into a Sales Agreement (as amended, the "Sales Agreement") with SVB Leerink LLC (the "Agent"), pursuant to which the Company could sell, from time to time, at its option, up to an aggregate amount of $75,000 of shares of the Company's common stock, $0.001 par value per share through the Agent, as the Company's sales agent. In June 2020, the 2019 Sales Agreement was amended to reduce the aggregate offering amount under the 2019 Sales Agreement from $75,000 of shares to $30,000 of shares.

On August 11, 2020, the 2019 Sales Agreement was terminated by the execution by the Company and the Agent of a new sales agreement, which was subsequently amended on October 21, 2020 (as amended, the “2020 Sales Agreement”). Under the 2020 Sales Agreement the Company may sell, from time to time, at its option, up to an aggregate of $62,500 of shares of the Company’s common stock, $0.001 par value per share (the “Shares”), through the Agent, as the Company’s sales agent.

Any Shares to be offered and sold under the 2020 Sales Agreement will be issued and sold (i) by methods deemed to be an "at the market offering" ("ATM"), as defined in Rule 415(a)(4) promulgated under the Securities Act of 1933, as amended or in negotiated transactions, if authorized by the Company, and (ii) pursuant to, and only upon the effectiveness of, a registration statement on Form S-3 filed by the Company with the Securities and Exchange Commission on August 11, 2020 for an offering of up to $350,000 of various securities, including shares of the Company’s common stock, preferred stock, debt securities, warrants and/or units for sale to the public in one or more public offerings.

Subject to the terms of the 2020 Sales Agreement, the Agent will use reasonable efforts to sell the Shares from time to time, based upon the Company’s instructions (including any price, time or size limits or other customary parameters or conditions the Company may impose). The Company cannot provide any assurances that it will issue any Shares pursuant to the 2020 Sales Agreement. The Company will pay the Agent a commission of up to 3.0% of the gross proceeds from the sale of the Shares, if any. The Company has also agreed to provide the Agent with customary indemnification rights. During the year ended March 31, 2020, the Company issued and sold 287,559 shares, respectively, of common stock under the 2019 Sales Agreement, for gross proceeds of $4,568 less offering fees of $137 for net proceeds of $4,431 under the ATM . The Company did not issue or sell any shares under the 2020 Sales Agreement during the year ended March 31, 2021.

Equity offerings

In November 2019, pursuant to an underwriting agreement (the “November 2019 Underwriting Agreement”) with J.P. Morgan Securities LLC and SVB Leerink LLC, as representatives of the several underwriters named therein (the “November 2019 Underwriters”), the Company issued and sold to the November 2019 Underwriters (a) 4,516,561 shares of the Company’s common stock (the “November 2019 Shares”), inclusive of the November 2019 Underwriters partially exercised 30-day option and purchased an additional 838,530 shares of the Company’s common stock, and (b) pre-funded warrants to purchase 2,200,000 shares of the Company’s common stock (the “November 2019 Pre-Funded Warrants”). The November 2019 shares were sold to the November 2019 Underwriters (the “November 2019 Offering”) at the public offering price of $13.61 per share and the pre-funded warrants were sold at a public offering price of $13.6099 per November 2019 Pre-Funded Warrant, which represented the per share public offering price for November 2019 Shares less a $0.0001 per share exercise price for each such November 2019 Pre-funded Warrant. The Company received aggregate net proceeds of approximately $85,598 in the November 2019 Offering, after deducting underwriting discounts, commissions and other offering expenses payable by the Company of approximately $5,814.

Funds affiliated with Redmile Group, LLC purchased all of the November 2019 Pre-Funded Warrants. The November 2019 Pre-Funded Warrants are exercisable at any time after the date of issuance. A holder of November 2019 Pre-Funded Warrants may not exercise the November 2019 Pre-Funded Warrant if the holder, together with its affiliates, would beneficially own more than 9.99% of the number of shares of the Company’s common stock outstanding immediately after giving effect to such exercise.

In June 2020, pursuant to an underwriting agreement (the “June 2020 Underwriting Agreement”) with J.P. Morgan Securities LLC and SVB Leerink LLC, as representatives of the several underwriters named therein (“the June 2020 Underwriters”), the Company sold to the June 2020 Underwriters (a) 3,478,261 shares of the Company’s common stock (the “June 2020 Shares”), inclusive of the underwrites 30-day option to purchase up to an additional 652,173 shares of the Company’s commons stock, and (b) pre-funded warrants to purchase 1,521,738 shares of the Company’s common stock (the “June 2020 Pre-Funded Warrants”).The June 2020 Shares of the Company’s common stock were sold to the June 2020 Underwriters at the public offering price of $23.00 per share and the June 2020 Pre-Funded Warrants were sold at a public offering price of $22.9999 per June 2020 Pre-Funded Warrant, which represented the per share public offering price for the June 2020 shares less a $0.0001 per share exercise price for each such June 2020 Pre-Funded Warrant. The Company received aggregate net proceeds of approximately $107,782 after deducting underwriting discounts, commissions and other offering expenses payable by the Company of approximately $7,217.

Funds affiliated with Redmile Group, LLC and funds affiliated with a second institutional investor purchased all of the June 2020 Pre-Funded Warrants. The June 2020 Pre-Funded Warrants are exercisable at any time after the date of issuance. A holder of June 2020 Pre-Funded Warrants may not exercise the June 2020 Pre-Funded Warrants if the holder, together with its affiliates, would beneficially own more than 9.99% of the number of shares of the Company’s common stock outstanding immediately after giving effect to such exercise. A holder of June 2020 Pre-Funded Warrants may increase or decrease this percentage up to 19.99% by providing at least 61 days’ prior notice to the Company.

In October 2020, pursuant to an underwriting agreement with J.P. Morgan Securities LLC and SVB Leerink LLC, as representatives of the several underwriters named therein, the Company issued and sold to the underwriters (a) 5,625,000 shares of the Company’s common stock, inclusive of the underwriters 30-day option to purchase up to an additional 937,500 shares of the Company’s common stock, and (b) pre-funded warrants to purchase 1,562,500 shares of the Company’s common stock (the “October 2020 Pre-Funded Warrants”). The shares of the Company’s common stock were sold to the underwriters at the public offering price of $40.00 per share and the pre-funded warrants were sold at a public offering price of $39.9999 per October 2020 Pre-Funded Warrant, which represented the per share public offering price for the Company’s common stock less a $0.0001 per share exercise price for each such pre-funded warrant. The Company received aggregate net proceeds of approximately $269,975 after deducting underwriting discounts, commissions and other offering expenses payable by the Company of approximately $17,525.

Funds affiliated with Redmile Group, LLC and funds affiliated with a second institutional investor purchased all of the October 2020 Pre-Funded Warrants. The October 2020 Pre-Funded Warrants are exercisable at any time after the date of issuance. A holder of October 2020 Pre-Funded Warrants may not exercise the October 2020 Pre-Funded Warrants if the holder, together with its affiliates, would beneficially own more than 9.99% of the number of shares of the Company’s common stock outstanding immediately after giving effect to such exercise. A holder of October 2020 Pre-Funded Warrants may increase or decrease this percentage up to 19.99% by providing at least 61 days’ prior notice to the Company.

Other than as set forth in Note 10 to these consolidated financial statements, including in the calculation of basic and diluted net loss per share attributable to common stockholders, the 5,284,238 shares of the Company’s common stock into which the November 2019 Pre-Funded Warrants, the June 2020 Pre-Funded Warrants and October 2020 Pre-Funded Warrants are exercisable are not included in the number of issued and outstanding shares of the Company’s common stock set forth herein. As of March 31, 2021, none of the November 2019 Pre-Funded Warrants, the June 2020 Pre-Funded Warrants, or the October 2020 Pre-Funded Warrants had been exercised.