Supplemental cash flow information related to our operating leases were as follows (in thousands):

Note 8. Short-Term Investments

As of December 31, 2021, and June 30, 2021, our short-term investments consisted of $173.2 million and $144.9 million, respectively, in U.S. government securities. The short-term investments held as of December 31, 2021 and June 30, 2021 had maturity dates of less than one year, are considered to be “held to maturity” and are carried at amortized cost. As of December 31, 2021, and June 30, 2021, the gross holding gains and losses were immaterial.

Impact of Restatement

We identified and corrected certain errors in the manner in which we recognized revenue from our License, Development and Commercialization Agreement with Kyowa Kirin Company ("KKC") (the "KKC Commercialization Agreement") with the result that revenue was overstated in some quarters and understated in other quarters in our financial statements during 2020 and 2021. The errors relate to the appropriate timing and amounts of revenue recognized at a point in time, including revenue from a historical cumulative catch-up adjustment and pass through services and over time under the cost-to-cost method associated with the KKC Commercialization Agreement (Note 3), including correction of the allocation of variable consideration between the various development service performance obligations. As a result, we determined that there were material errors in the financial statements that required a restatement of the financial statements for the three and six months ended December 31, 2021 and 2020 included in the Original Quarterly Report.

The following tables reflect the impact of the restatement adjustments to the specific line items presented in our previously reported financial statements for the periods indicated. The amounts originally reported were derived from the Original Quarterly Report (in thousands, except per share amounts):

Liquidity

We have accumulated losses of $349.4 million since inception and expect to incur operating losses and generate negative cash flows from operations for the foreseeable future. As of December 31, 2021, we had $185.8 million in cash and cash equivalents and short-term investments. We believe that these resources will be sufficient to meet our obligations and fund our liquidity and capital expenditure requirements for at least the next 12 months from the issuance of these financial statements. Our current business operations are focused on continuing the clinical development of our drug candidates. Changes to our research and development plans or other changes affecting our operating expenses may affect actual future use of existing cash resources. Our research and development expenses are expected to increase in the foreseeable future. We cannot determine with certainty costs associated with ongoing and future clinical trials or the regulatory approval process. The duration, costs and timing associated with the development of our product candidates will depend on a variety of factors, including uncertainties associated with the results of our clinical trials.

To date, we have obtained cash and funded our operations primarily through equity financings and license agreements. In order to continue the development of our drug candidates, at some point in the future we expect to pursue one or more capital transactions, whether through the sale of equity securities, debt financing, license agreements or entry into strategic partnerships. There can be no assurance that we will be able to continue to raise additional capital in the future.

Reclassifications

Certain reclassifications have been made to the prior year financial statements to conform to the current year financial statement presentation of unbilled receivables and cash flows from financing activities. These changes did not impact previously reported net loss, loss per share, stockholders’ equity, total assets or cash flows.

Revenue Recognition

Accounting Standards Codification ("ASC") Topic 606, Revenue from Contracts with Customers (“Topic 606”)

We recognize revenue when control of the promised goods or services is transferred to our customers, in an amount that reflects the consideration we expect to be entitled to in exchange for those goods or services. For enforceable contracts with our customers, we first identify the distinct performance obligations – or accounting units – within the contract. Performance obligations are commitments in a contract to transfer a distinct good or service to the customer.

Payments received under commercial arrangements, such as licensing technology rights, may include non-refundable fees at the inception of the arrangements, milestone payments for specific achievements designated in the agreements, and royalties on the sale of products. At the inception of arrangements that include milestone payments, we use judgment to evaluate whether the milestones are

probable of being achieved and we estimate the amount to include in the transaction price using the most likely method. If it is probable that a significant revenue reversal will not occur, the estimated amount is included in the transaction price. Milestone payments that are not within our or the licensee’s control, such as regulatory approvals, are not included in the transaction price until those approvals are received. At the end of each reporting period, we re-evaluate the probability of achievement of development milestones and any related constraint and, as necessary, we adjust our estimate of the overall transaction price. Any adjustments are recorded on a cumulative catch-up basis, which would affect revenues and earnings in the period of adjustment.

We develop estimates of the stand-alone selling price for each distinct performance obligation. Variable consideration that relates specifically to our efforts to satisfy specific performance obligations is allocated entirely to those performance obligations. Other components of the transaction price are allocated based on the relative stand-alone selling price, over which management has applied significant judgment. We develop assumptions that require judgment to determine the stand-alone selling price for license-related performance obligations, which may include forecasted revenues, development timelines, reimbursement rates for personnel costs, discount rates and probabilities of technical, regulatory and commercial success. We estimate stand-alone selling price for research and development performance obligations by forecasting the expected costs of satisfying a performance obligation plus an appropriate margin.

In the case of a license that is a distinct performance obligation, we recognize revenue allocated to the license from non-refundable, up-front fees at the point in time when the license is transferred to the licensee and the licensee can use and benefit from the license. For licenses that are bundled with other distinct or combined obligations, we use judgment to assess the nature of the performance obligation to determine whether the performance obligation is satisfied over time or at a point in time and, if over time, the appropriate method of measuring progress for purposes of recognizing revenue. If the performance obligation is satisfied over time, we evaluate the measure of progress each reporting period and, if necessary, adjust the measure of performance and related revenue recognition. From time to time, we perform additional services for KKC at their request, the costs of which are fully reimbursed to us. We record the reimbursement of such pass through services as revenue at 100% of reimbursed costs as control of the additional services for KKC is transferred at the time we incur such costs. The costs we incur for these additional services are incurred solely for the benefit of KKC and have no alternative use to us.

The selection of the method to measure progress towards completion requires judgment and is based on the nature of the products or services to be provided. Revenue is recorded proportionally as costs are incurred. We generally use the cost-to-cost measure of progress because it best depicts the transfer of control to the customer which occurs as we incur costs. Under the cost-to-cost measure of progress, the extent of progress towards completion is measured based on the ratio of costs incurred to date to the total estimated costs at completion of the performance obligation (an “input method” under Topic 606). We use judgment to estimate the total cost expected to complete the research and development performance obligations, which include subcontractors’ costs, labor, materials, other direct costs and an allocation of indirect costs. We evaluate these cost estimates and the progress each reporting period and, as necessary, we adjust the measure of progress and related revenue recognition.

For arrangements that include sales-based or usage-based royalties, we recognize revenue at the later of (i) when the related sales occur or (ii) when the performance obligation to which some or all of the royalty has been allocated has been satisfied or partially satisfied. To date, we have not recognized any sales-based or usage-based royalty revenue from license agreements.

The KKC Commercialization Agreement and KKC Japan License Agreement (Note 3) included other distinct performance obligations satisfied over time, and accordingly we recognized $19.6 million and $18.9 million related to our progress toward satisfying those obligations during the six months ended December 31, 2021 and 2020, respectively.

Based on the characteristics of the Helsinn License Agreement (Note 3), we recognized revenue based on the extent of progress towards completion of the performance obligations. The Helsinn License Agreement was terminated in November 2021.

Contract Balances

Contract liabilities are included in “Deferred revenue” and “Deferred revenue long-term”. The following table presents changes in accounts receivable, unbilled receivables, and contract liabilities accounted for under Topic 606 during the six months ended December 31, 2021 and 2020 (in thousands):

The timing of revenue recognition, invoicing and cash collections results in billed accounts receivable and unbilled receivables and deferred revenue (contract liabilities). We invoice our customers in accordance with agreed-upon contractual terms, typically at periodic intervals or upon achievement of contractual milestones. Invoicing may occur subsequent to revenue recognition, resulting in unbilled receivables. We may receive advance payments from our customers before revenue is recognized, resulting in contract liabilities. The unbilled receivables and deferred revenue reported on the Condensed Balance Sheets relate to the KKC Commercialization Agreement.

As of December 31, 2021, we had $98.0 million of deferred revenue associated with the KKC Commercialization Agreement, of which $64.5 million relates to the U.S. license which is a unit of account under the scope of Topic 808 and is not a deliverable under Topic 606, and $33.5 million relates to the development services performance obligations which are under the scope of Topic 606.

Our contract liabilities accounted for under Topic 606 relate to the amount of initial upfront consideration that was allocated to the development services performance obligations. Contract liabilities are recognized over the duration of the performance obligations based on the costs incurred relative to total expected costs.

Revenues from Collaborators

We earn revenue in connection with collaboration agreements, which are described in Note 3. License Agreements.

At contract inception, we assess whether the collaboration arrangements are within the scope of ASC Topic 808, Collaborative Arrangements (“Topic 808”), to determine whether such arrangements involve joint operating activities performed by parties that are both active participants in the activities and exposed to significant risks and rewards dependent on the commercial success of such activities. This assessment is performed based on the responsibilities of all parties in the arrangement. For collaboration arrangements within the scope of Topic 808 that contain multiple units of account, we first determine which units of account within the arrangement are within the scope of Topic 808 and which elements are within the scope of Topic 606. For units of account within collaboration arrangements that are accounted for pursuant to Topic 808, an appropriate recognition method is determined and applied consistently, by analogy to authoritative accounting literature. For elements of collaboration arrangements that are accounted for pursuant to Topic 606, we recognize revenue as discussed above. Consideration received that does not meet the requirements to satisfy Topic 606 revenue recognition criteria is recorded as deferred revenue in the accompanying Condensed Balance Sheets, classified as either short-term or long-term deferred revenue based on our best estimate of when such amounts will be recognized.

Share-based Compensation

Share-based compensation expense for employees and directors is recognized in the Condensed Statement of Operations based on estimated amounts, including the grant date fair value and the expected service period. For stock options, we estimate the grant date fair value using a Black-Scholes valuation model, which requires the use of multiple subjective inputs including estimated future volatility, expected forfeitures and the expected term of the awards. We estimate the expected future volatility based on the stock’s historical price volatility. The stock’s future volatility may differ from the estimated volatility at the grant date. For restricted stock unit (“RSU”) equity awards, we estimate the grant date fair value using our closing stock price on the date of grant. We recognize the effect of forfeitures in compensation expense when the forfeitures occur. The estimated forfeiture rates may differ from actual forfeiture rates which would affect the amount of expense recognized during the period. We recognize the value of the awards over the awards’ requisite service or performance periods. The requisite service period is generally the time over which our share-based awards vest.

Leases

We account for our leases under FASB ASC Topic 842, Leases (“ASC 842”). Leases which are identified within the scope of ASC 842 and which have a term greater than one year are recognized on our Condensed Balance Sheet as ROU assets and lease liabilities. Operating lease liabilities and their corresponding ROU assets are recorded based on the present value of lease payments over the expected remaining lease term. The lease term includes any renewal options and termination options that we are reasonably certain to exercise. Certain adjustments to the right-of-use asset may be required for items such as initial direct costs paid or incentives received. The present value of lease payments is determined by using the interest rate implicit in the lease, if that rate is readily determinable; otherwise, we use our incremental borrowing rate. The incremental borrowing rate is determined based on the rate of interest that we would pay to borrow on a collateralized basis an amount equal to the lease payments for a similar term and in a similar economic environment. The interest rate implicit in lease contracts to calculate the present value is typically not readily determinable. As such, significant management judgment is required to estimate the incremental borrowing rate.

Rent expense for operating leases is recognized on a straight-line basis over the lease term based on the total lease payments. We have elected the practical expedient to not separate lease and non-lease components for our real estate leases. Our non-lease components are primarily related to property maintenance, which varies based on future outcomes, and thus is recognized in rent expense when incurred.