Cardiff Oncology (CRDF) 10-K 25 Feb 21 2020 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2020	Feb. 18, 2021	Jun. 30, 2020
Document and Entity Information
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2020
Current Fiscal Year End Date	--12-31
Document Transition Report	false
Entity File Number	001-35558
Entity Registrant Name	CARDIFF ONCOLOGY, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	27-2004382
Entity Address, State or Province	CA
Entity Address, City or Town	San Diego
Entity Address, Address Line One	11055 Flintkote Avenue
Entity Address, Postal Zip Code	92121
City Area Code	858
Local Phone Number	952-7570
Title of 12(b) Security	Common Stock, $0.0001 par value
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	true
ICFR Auditor Attestation Flag	false
Entity Shell Company	false
Entity Public Float			$ 103,720,151
Entity Common Stock, Shares Outstanding (shares)		37,052,129
Entity Central Index Key	0001213037
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Amendment Flag	false

Balance Sheets

Balance Sheets - USD ($)	Dec. 31, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 130,980,681	$ 10,195,292
Accounts receivable and unbilled receivable	320,458	203,480
Prepaid expenses and other assets	2,055,321	954,957
Total current assets	133,356,460	11,353,729
Property and equipment, net	623,694	877,823
Operating lease right-of-use assets	343,001	697,418
Other assets	404,232	157,576
Total Assets	134,727,387	13,086,546
Current liabilities:
Accounts payable	1,366,008	656,304
Accrued liabilities	3,850,763	3,260,061
Operating lease liabilities	860,206	865,379
Other current liabilities	42,000	0
Total current liabilities	6,118,977	4,781,744
Derivative financial instruments—warrants	284,971	4,127
Operating lease liabilities, net of current portion	9,291	860,963
Other liabilities	156,266	128,368
Total liabilities	6,569,505	5,775,202
Commitments and contingencies
Stockholders’ equity
Preferred stock, $0.001 par value, 20,000,000 shares authorized; (Note 5)	716	60
Common stock, $0.0001 par value, 150,000,000 shares authorized; 36,780,805 and 8,593,633 shares issued and outstanding at December 31, 2020 and December 31, 2019, respectively	3,678	8,312
Additional paid-in capital	361,820,025	217,172,528
Service receivables	(2,171,258)	(971,673)
Accumulated deficit	(231,495,279)	(208,897,883)
Total stockholders’ equity	128,157,882	7,311,344
Total Liabilities and Stockholders’ Equity	$ 134,727,387	$ 13,086,546

Balance Sheets (Parenthetical)

Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized (in shares)	20,000,000	20,000,000
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	150,000,000	150,000,000
Common stock, shares issued (in shares)	36,780,805	8,593,633
Common stock, shares outstanding (in shares)	36,780,805	8,593,633

Statements of Operations

Statements of Operations - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Total revenues	$ 365,993	$ 244,632
Costs and expenses:
Research and development	11,235,396	11,162,236
Selling, general and administrative	8,216,471	5,760,890
Total operating expenses	19,451,867	16,923,126
Loss from operations	(19,085,874)	(16,678,494)
Interest income	89,809	234,169
Interest expense	(1,519)	0
Other gain (loss), net	(28,244)	1,978
Gain (loss) from changes in fair value of derivative financial instruments—warrants	(280,844)	28,188
Net loss	(19,306,672)	(16,414,159)
Preferred stock dividend payable on Series A Convertible Preferred Stock	(24,240)	(24,240)
Net loss attributable to common stockholders	$ (22,597,396)	$ (16,706,668)
Net loss per common share - basic and diluted (in dollars per share)	$ (1.08)	$ (2.80)
Weighted-average shares outstanding - basic and diluted (in shares)	20,874,665	5,973,906
Royalties
Royalties	$ 365,993	$ 243,137
Services
Services	0	1,495
Series C Convertible Preferred Stock
Costs and expenses:
Deemed dividend recognized on beneficial conversion features of Convertible Preferred Stock issuance	0	(268,269)
Series D Convertible Preferred Stock
Costs and expenses:
Deemed dividend recognized on beneficial conversion features of Convertible Preferred Stock issuance	(601,767)	0
Series E Convertible Preferred Stock
Costs and expenses:
Deemed dividend recognized on beneficial conversion features of Convertible Preferred Stock issuance	$ (2,664,717)	$ 0

Statements of Stockholders' Equ

Statements of Stockholders' Equity - USD ($)		Total	Series D Convertible Preferred Stock	Series E Convertible Preferred Stock	Preferred Stock	Preferred StockSeries D Convertible Preferred Stock	Preferred StockSeries E Convertible Preferred Stock	Common Stock	Common StockSeries D Convertible Preferred Stock	Common StockSeries E Convertible Preferred Stock	Additional Paid-In Capital	Additional Paid-In CapitalSeries D Convertible Preferred Stock	Additional Paid-In CapitalSeries E Convertible Preferred Stock	Service Receivable	Accumulated Deficit	Accumulated DeficitSeries D Convertible Preferred Stock	Accumulated DeficitSeries E Convertible Preferred Stock
Balance (in shares) at Dec. 31, 2018					60,600			3,831,879
Balance at Dec. 31, 2018		$ 10,084,192			$ 60			$ 7,742			$ 202,267,605			$ 0	$ (192,191,215)
Increase (Decrease) in Stockholders' Equity
Sale of common stock and warrants, net of expenses (in shares)								1,994,929
Sale of common stock and warrants, net of expenses		8,817,772						$ 199			8,817,573
Issuance of common stock, preferred stock and warrants for clinical trial funding commitment, net of expenses and discount (in shares)					200,000			183,334
Issuance of common stock, preferred stock and warrants for clinical trial funding commitment, net of expenses and discount		(40,000)			$ 200			$ 110			1,634,690			(1,675,000)
Stock-based compensation		884,942									884,942
Issuance of common stock upon exercise of warrants (in shares)								2,221,635
Issuance of common stock upon exercise of warrants		3,299,510						$ 223			3,299,287
Issuance of common stock upon vesting of restricted stock awards (in shares)								22,057
Issuance of common stock upon vesting of restricted stock awards		0						$ 5			(5)
Deemed dividend recognized on beneficial conversion features of Series C Convertible Preferred Stock issuance		0									268,269				(268,269)
Issuance of common stock upon conversion of Convertible Preferred Stock (in shares)					(200,000)			333,333
Issuance of common stock upon conversion of Convertible Preferred Stock		0			$ (200)			$ 33			167
Preferred stock dividend payable on Series A Convertible Preferred Stock		(24,240)													(24,240)
Issuance of common stock for share rounding as a result of reverse stock split (in shares)								6,466
Release of clinical trial funding commitment		703,327												703,327
Net loss		(16,414,159)													(16,414,159)
Balance (in shares) at Dec. 31, 2019					60,600			8,593,633
Balance at Dec. 31, 2019		7,311,344			$ 60			$ 8,312			217,172,528			(971,673)	(208,897,883)
Increase (Decrease) in Stockholders' Equity
Issuance of common stock, preferred stock and warrants for clinical trial funding commitment, net of expenses and discount (in shares)					154,670			602,833
Issuance of common stock, preferred stock and warrants for clinical trial funding commitment, net of expenses and discount		(7,500)			$ 15			$ 60			2,292,425			(2,300,000)
Stock-based compensation		1,764,804									1,764,804
Issuance of common stock upon exercise of warrants (in shares)								12,138,469
Issuance of common stock upon exercise of warrants		24,871,586						$ 1,214			24,870,372
Issuance of common stock upon vesting of restricted stock awards (in shares)								10,810
Issuance of common stock upon vesting of restricted stock awards		0						$ 1			(1)
Deemed dividend recognized on beneficial conversion features of Series C Convertible Preferred Stock issuance			$ 0	$ 0								$ 601,767	$ 2,664,717			$ (601,767)	$ (2,664,717)
Issuance of common stock upon conversion of Convertible Preferred Stock (in shares)						(154,670)	(210,780)		1,546,700	863,852
Issuance of common stock upon conversion of Convertible Preferred Stock			$ 0	$ 0		$ (15)	$ (210)		$ 155	$ 86		$ (140)	$ 124
Preferred stock dividend payable on Series A Convertible Preferred Stock		(24,240)													(24,240)
Release of clinical trial funding commitment		1,100,415												1,100,415
Net loss		(19,306,672)													(19,306,672)
Sale of stock, shares issued (in shares)	[1]				865,824			12,964,313
Net proceeds	[1]	112,299,949			$ 866			$ 1,297			112,297,786
Common Stock par value adjustment		0						$ (7,453)			7,453
Issuance of common stock upon exercise of stock options (in shares)								60,195
Issuance of common stock upon exercise of stock options		148,196						$ 6			148,190
Balance (in shares) at Dec. 31, 2020					715,644			36,780,805
Balance at Dec. 31, 2020		$ 128,157,882			$ 716			$ 3,678			$ 361,820,025			$ (2,171,258)	$ (231,495,279)
[1]	Net of expenses of $7,507,123, and fair value of warrants issued as a transaction advisory fee as of the date of issuance of $370,666

Statement of Shareholders' Equi

Statement of Shareholders' Equity (Parenthetical)	12 Months Ended
	Dec. 31, 2020USD ($)
Statement of Stockholders' Equity [Abstract]
Cost of Issuance of Common Stock, Preferred Stock and Warrants for Clinical Trial Funding Commitment	$ 7,507,123
Fair value	$ 370,666

Statements of Cash Flows

Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Operating activities
Net loss	$ (19,306,672)	$ (16,414,159)
Adjustments to reconcile net loss to net cash used in operating activities:
Impairment loss	34,169	0
Depreciation	466,009	494,232
Stock-based compensation expense	1,764,804	884,943
Change in fair value of derivative financial instruments—warrants	280,844	(28,188)
Release of clinical trial funding commitment	1,100,415	703,327
Changes in operating assets and liabilities:
Other assets	(246,656)	(54,778)
Accounts receivable and unbilled receivable	(116,978)	(35,725)
Prepaid expenses and other current assets	(1,100,364)	115,459
Operating lease right-of-use assets	320,248	302,491
Accounts payable and accrued expenses	1,276,166	1,455,336
Operating lease liabilities	(856,845)	(776,806)
Other liabilities	69,898	86,368
Net cash used in operating activities	(16,314,962)	(13,267,500)
Investing activities
Capital expenditures	(211,880)	(67,622)
Net cash used in investing activities	(211,880)	(67,622)
Financing activities
Proceeds from sale of common stock, preferred stock and warrants, net of expenses of $7,507,123 and $158,678 respectively	112,299,949	8,817,772
Costs related to the clinical trial funding commitment	(7,500)	(40,000)
Proceeds from exercise of warrants	24,871,586	3,299,509
Proceeds from exercise of options	148,196	0
Borrowings under note payable	305,000	0
Repayments of note payable	(305,000)	0
Net cash provided by financing activities	137,312,231	12,077,281
Net change in cash and cash equivalents	120,785,389	(1,257,841)
Cash and cash equivalents—Beginning of period	10,195,292	11,453,133
Cash and cash equivalents—End of period	130,980,681	10,195,292
Supplementary disclosure of cash flow activity:
Cash paid for taxes	800	800
Supplemental disclosure of non-cash investing and financing activities:
Preferred stock dividend payable on Series A Convertible Preferred Stock	24,240	24,240
Series C Convertible Preferred Stock
Supplemental disclosure of non-cash investing and financing activities:
Deemed dividend recognized on beneficial conversion features of convertible preferred stock	0	268,269
Common stock, Series C Convertible Preferred Stock and warrants issued in connection with clinical trial funding commitment, net of discount of $235,640	0	1,675,000
Common stock issued upon conversion of Convertible Preferred Stock	0	33
Series D Convertible Preferred Stock
Supplemental disclosure of non-cash investing and financing activities:
Deemed dividend recognized on beneficial conversion features of convertible preferred stock	601,767	0
Common stock, Series C Convertible Preferred Stock and warrants issued in connection with clinical trial funding commitment, net of discount of $235,640	2,300,000	0
Common stock issued upon conversion of Convertible Preferred Stock	155	0
Series E Convertible Preferred Stock
Supplemental disclosure of non-cash investing and financing activities:
Deemed dividend recognized on beneficial conversion features of convertible preferred stock	2,664,717	0
Common stock issued upon conversion of Convertible Preferred Stock	$ 86	$ 0

Statements of Cash Flows (Paren

Statements of Cash Flows (Parenthetical) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Common Stock And Warrants
Payments of stock issuance costs	$ 7,507,123	$ 158,678
Series C Convertible Preferred Stock
Discount of issuance of common stock, preferred stock and warrants for clinical trial funding commitment		$ 235,640
Series D Convertible Preferred Stock
Discount of issuance of common stock, preferred stock and warrants for clinical trial funding commitment	$ 488,270

Business Overview and Liquidity

Business Overview and Liquidity	12 Months Ended
	Dec. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Business Overview and Liquidity	Business Overview and Liquidity Business Organization and Overview Cardiff Oncology, Inc. (“Cardiff Oncology” or the “Company”) headquartered in San Diego, California, is a clinical-stage biotechnology company with the singular mission of developing new treatment options for cancer patients in indications with the greatest medical need, including KRAS-mutated metastatic colorectal cancer, pancreatic cancer, Zytiga®-resistant metastatic castration-resistant prostate cancer and leukemias. Our goal is to overcome resistance, improve response to treatment and increase overall survival. Through the integration of tumor genomics and biomarker technology, we are able to assess patient response to treatment. Liquidity The Company has incurred net losses since its inception and has negative operating cash flows. As of December 31, 2020, the Company had $131.0 million in cash and cash equivalents and believes it has sufficient cash to meet its funding requirements for at least the next 12 months following the issuance date of these financial statements. For the foreseeable future, the Company expects to continue to incur losses and require additional capital to further advance its clinical trial programs and support its other operations. The Company cannot be certain that additional funding will be available on acceptable terms, or at all. To the extent that the Company can raise additional funds by issuing equity securities, the Company’s stockholders may experience additional dilution. The economic effects of COVID-19 could also have an adverse effect on the Company's ability to raise additional capital. See Note 13 to the financial statements for further information.

Basis of Presentation and Summa

Basis of Presentation and Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Basis of Presentation and Summary of Significant Accounting Policies	Basis of Presentation and Summary of Significant Accounting Policies The accompanying financial statements of Cardiff Oncology have been prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”). The Company made a reverse split of its common stock, $0.0001 par value, at a ratio of 1 for 6, effective February 19, 2019. All share and per share information in the financial statements and the accompanying notes have been retroactively adjusted to reflect the reverse stock split for all periods presented. Segment Reporting Operating segments are identified as components of an enterprise about which separate discrete financial information is available for evaluation by the chief operating decision-maker in making decisions regarding resource allocation and assessing performance. The Company views its operations as, and manages its business in, one operating segment. Use of Estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make significant estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. The most significant estimates involve accrued clinical trial expenses and determining the assumptions made for stock-based compensation. Accrued Clinical Trial Expenses The Company expenses research and development expenditures as incurred, which include costs related to clinical trial activities. The Company accrues costs for clinical trial activities based upon estimates of the services received and related expenses incurred that have yet to be invoiced by the clinical research organizations (CROs), investigators, professional service providers, and other vendors providing clinical trial services (collectively, the “service providers”). As of December 31, 2020 the Company’s Clinical trial accrual balance of $1,683,195 is included in accrued liabilities and other liabilities. The Company’s related 2020 clinical trial expenses are included in research and development expense of $11,235,396. Certain accrued clinical trial expenses are released from service receivables classified within equity (see Note 5) as clinical trial services are performed. Cash and Cash Equivalents Cash and cash equivalents consist of operating and money market accounts as of December 31, 2020 and 2019 on deposit. Cash equivalents are considered by the Company to be highly liquid investments purchased with original maturities of three months or less from the date of purchase. Concentration of Credit Risk Financial instruments that potentially subject the Company to significant concentrations of credit risk consist primarily of cash and cash equivalents. The Company maintains deposit accounts at financial institutions that are in excess of federally insured limits. The Company has not experienced any losses in such accounts and believes it is not exposed to significant risk on its cash due to the financial position of the depository institution in which those deposits are held. The Company limits its exposure to credit loss by generally placing its cash in high credit quality financial institutions and investment in non FDIC insured money market funds denominated and payable in U.S. dollars. Additionally, the Company has established guidelines regarding diversification of its investments and their maturities, which are designed to maintain principal and maximize liquidity. Revenues The Company recognizes revenue when control of its products and services are transferred to its customers in an amount that reflects the consideration it expects to receive from its customers in exchange for those products and services. This process involves identifying the contract with a customer, determining the performance obligations in the contract, determining the contract price, allocating the contract price to the distinct performance obligations in the contract, and recognizing revenue when the performance obligations have been satisfied. A performance obligation is considered distinct from other obligations in a contract when it provides a benefit to the customer either on its own or together with other resources that are readily available to the customer and is separately identified in the contract. The Company considers a performance obligation satisfied once it has transferred control of goods or service to the customer, meaning the customer has the ability to use and obtain the benefit of goods or service. The Company recognizes revenue for satisfied performance obligations only when it determines there are no uncertainties regarding payment terms or transfer of control. For sales-based royalties, the Company recognizes 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). Royalty and License Revenues The Company licenses and sublicenses its patent rights to healthcare companies, medical laboratories and biotechnology partners. These agreements may involve multiple elements such as license fees, royalties and milestone payments. Revenue is recognized when the criteria described above have been met as well as the following: • Up-front nonrefundable license fees pursuant to agreements under which the Company has no continuing performance obligations are recognized as revenues on the effective date of the agreement and when collection is probable. • Minimum royalties are recognized as earned, and royalties are earned based on the licensee’s use. The Company estimates and records licensee’s sales based on historical usage rate and collectability. • For sales-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). Payment terms and conditions vary by contracts, although terms generally include a requirement of payment within 30 to 45 days after invoice. Minimum royalties are generally due quarterly or annually. Derivative Financial Instruments—Warrants The Company has issued common stock warrants in connection with the execution of certain equity financings. Such warrants are classified as derivative liabilities and are recorded at their fair market value as of each reporting period. Such warrants do not meet the exemption that a contract should not be considered a derivative instrument if it is (1) indexed to its own stock and (2) classified in stockholders’ equity. The warrants contain a feature that could require the transfer of cash in the event a change of control occurs without an authorization of the Company’s Board of Directors, and therefore classified as a liability. Changes in fair value of derivative liabilities are recorded in the statement of operations under the caption “Change in fair value of derivative instruments — warrants.” The fair value of warrants is determined using the Black-Scholes option-pricing model using assumptions regarding the historical volatility of Cardiff Oncology’s common stock price, the remaining life of the warrants, and the risk-free interest rates at each period end. The Company thus uses model-derived valuations where inputs are observable in active markets to determine the fair value. The use of the Black-Scholes model classifies such warrants as Level 3 (See " Fair Value of Financial Instruments" below). At December 31, 2020 and 2019, the fair value of these warrants was $284,971 and $4,127, respectively, and was recorded as a liability under the caption “derivative financial instruments — warrants” on the balance sheets. Stock-Based Compensation Stock-based compensation expense is measured at the grant date based on the estimated fair value of the award and is recognized straight-line over the requisite service period of the individual grants, which typically equals the vesting period. Fair Value of Financial Instruments Financial instruments consist of cash equivalents, accounts receivable, accounts payable and derivative liabilities. The Company applies ASC 820 for financial assets and liabilities that are required to be measured at fair value and non-financial assets and liabilities that are not required to be measured at fair value on a recurring basis. These financial instruments are stated at their respective historical carrying amounts, which approximate fair value due to their short-term nature as they reflect current market interest rates. The authoritative guidance establishes a fair value hierarchy that is based on the extent and level of judgment used to estimate the fair value of assets and liabilities. In general, the authoritative guidance requires us to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. An asset or liability’s categorization within the fair value hierarchy is based upon the lowest level of input that is significant to the measurement of its fair value. The three levels of input defined by the authoritative guidance are as follows: The Company measures certain assets and liabilities at fair value on a recurring basis using the three-tier fair value hierarchy, which prioritizes the inputs used in measuring fair value. The three tiers include: • Level 1 — Quoted prices for identical instruments in active markets. • Level 2 — Quoted prices for similar instruments in active markets; quoted prices for identical or similar instruments in markets that are not active; and model-derived valuations where inputs are observable or where significant value drivers are observable. • Level 3 — Instruments where significant value drivers are unobservable to third parties. Long-Lived Assets Long-lived assets consist of property and equipment. The Company records property and equipment at cost, and records other intangible assets based on their fair values at the date of acquisition. Depreciation on property and equipment is calculated using the straight-line method over the estimated useful life of five years for laboratory equipment and three Impairment losses on long-lived assets used in operations are recorded when indicators of impairment are present and the undiscounted cash flows estimated to be generated by those assets are less than the assets carrying amount. If such assets are considered to be impaired, the impairment to be recognized is measured by the amount by which the carrying amount of the assets exceeds the estimated fair value of the assets. Leases The Company determines if an arrangement is a lease at inception. Operating leases are included in operating lease right-of-use (“ROU”) assets, current operating lease liabilities and non-current operating lease liabilities in the Company’s balance sheets. ROU assets represent the Company’s right to use an underlying asset for the lease term and lease liabilities represent its obligation to make lease payments arising from the lease. Operating lease ROU assets and liabilities are recognized at commencement date based on the present value of lease payments over the lease term. As most of the Company’s operating leases do not provide an implicit rate, the Company uses its incremental borrowing rate based on the information available at commencement date in determining the present value of lease payments. The incremental borrowing rate is the rate of interest that the Company would expect to pay to borrow on a collateralized and fully amortizing basis over a similar term an amount equal to the lease payments in a similar economic environment. The operating lease ROU asset also includes any lease payments made less lease incentives received. The Company’s lease terms may include options to extend or terminate the lease when it is reasonably certain that the Company will exercise that option. Lease expense is recognized on a straight-line basis over the lease term. Our facilities lease agreement contains lease and non-lease components, such as common area maintenance. We have elected to account for these lease and non-lease components of this agreement as a single lease component. Leases with an initial term of 12 months or less are not recorded on the Company's balance sheets. These short-term leases are expensed on a straight-line basis over the lease term. Income Taxes Income taxes are determined using the asset and liability approach of accounting for income taxes. Under this approach, deferred taxes represent the future tax consequences expected to occur when the reported amounts of assets and liabilities are recovered or paid. Deferred taxes result from differences between the financial statement and tax bases of Cardiff Oncology’s assets and liabilities and are adjusted for changes in tax rates and tax laws when changes are enacted. Valuation allowances are recorded to reduce deferred tax assets when it is more likely than not that a tax benefit will not be realized. The assessment of whether or not a valuation allowance is required often requires significant judgment. Contingencies In the normal course of business, Cardiff Oncology is subject to loss contingencies, such as legal proceedings and claims arising out of its business, that cover a wide range of matters, including, among others, government investigations, stockholder lawsuits, product and environmental liability, and tax matters. In accordance with FASB ASC Topic 450, Contingencies , Cardiff Oncology records such loss contingencies when it is probable that a liability has been incurred and the amount of loss can be reasonably estimated. Cardiff Oncology, in accordance with this guidance, does not recognize gain contingencies until realized. Research and Development Research and development expenses include expenditures in connection with an in-house research and development laboratory, salaries and staff costs, clinical trials, purchased in-process research and development and regulatory and scientific consulting fees, as well as contract research and insurance. Also, patent filing and maintenance expenses are considered legal in nature and therefore classified as general and administrative expense, if any. Non-refundable advance payments for goods or services that will be used or rendered for future research and development activities are deferred and capitalized. As the related goods are delivered or the services are performed, or when the goods or services are no longer expected to be provided, the deferred amounts are recognized as an expense. Net Loss Per Share Basic and diluted net loss per common share is determined by dividing net loss applicable to common stockholders by the weighted-average common shares outstanding during the period. Preferred dividends and deemed dividends recognized in connection with certain preferred share issuances are included in net loss attributable to common stockholders in the computation of basic and diluted earnings per share. For all periods presented, there is no difference in the number of shares used to calculate basic and diluted shares outstanding as inclusion of the potentially dilutive securities would be antidilutive. Shares used in calculating diluted net loss per common share exclude as anti-dilutive the following share equivalents: December 31, 2020 2019 Options to purchase Common Stock 1,860,507 1,015,418 Warrants to purchase Common Stock 5,260,992 10,589,482 Restricted Stock Units 491 11,301 Series A Convertible Preferred Stock 877 877 Series E Convertible Preferred Stock 2,684,607 — 9,807,474 11,617,078 Recently Adopted Accounting Pronouncement In August 2018, the FASB issued ASU No. 2018-13 ("ASU 2018-13"), Changes to the Disclosure Requirements for Fair Value Measurement . This ASU eliminates, adds and modifies certain disclosure requirements for fair value measurements as part of its disclosure framework project. The standard is effective for all entities for financial statements issued for fiscal years beginning after December 15, 2019, and interim periods within those fiscal years. The Company has prospectively adopted ASU 2018-13 as of January 1, 2020 for periods presented after adoption. The adoption of ASU 2018-13 did not have a material impact on the Company's financial statements. In August 2020, the FASB issued ASU No. 2020-06 ("ASU 2020-06"), Debt - Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging - Contracts in Entity’s Own Equity (Subtopic 815-40) (“ASU 2020-06”)

Supplementary Balance Sheet Inf

Supplementary Balance Sheet Information	12 Months Ended
	Dec. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Supplementary Balance Sheet Information	Supplementary Balance Sheet Information Property and Equipment Fixed assets consist of furniture and office equipment, leasehold improvements and laboratory equipment. Depreciation expense for property and equipment for the years ended December 31, 2020 and 2019 was $466,009 and $494,232, respectively. Property and equipment consisted of the following: As of December 31, 2020 2019 Furniture and office equipment $ 797,739 $ 775,030 Leasehold improvements 1,962,230 1,962,230 Laboratory equipment 867,750 744,856 3,627,719 3,482,116 Less—accumulated depreciation (3,004,025) (2,604,293) Property and equipment, net $ 623,694 $ 877,823 Accrued Liabilities Accrued liabilities consisted of the following: As of December 31, 2020 2019 Accrued compensation $ 1,523,321 $ 1,003,383 Preferred stock dividend 389,495 365,255 Clinical trials 1,557,134 1,504,660 Research agreements and services 66,593 181,408 Director fees 92,500 67,500 Professional fees and outside services 38,180 21,000 Patent, license and other fees 117,440 69,950 Other accrued liabilities 66,100 46,905 Total accrued liabilities $ 3,850,763 $ 3,260,061

Leases

Leases	12 Months Ended
	Dec. 31, 2020
Leases [Abstract]
Leases	Leases As a lessee, the Company’s current leases include its master facility lease and immaterial equipment leases, all of which are considered operating leases. The Company (as a sublessor) also subleases portions of its facility to third parties under three separate subleases. All of these subleases have been determined to be operating leases and are accounted for separately from the head lease. Master Facility Lease The Company leases a building in San Diego under an operating lease that expires on December 31, 2021. The lease currently requires fixed monthly rent payments of approximately $78,000, with 3% annual escalation. Facility Subleases As a result of corporate restructurings in previous years, the Company vacated a portion of its facility and has subleased space to third parties under three separate sublease agreements, which all expire December 31, 2021. Income is recognized on a straight-line basis over the term of the sublease. Impairment of Right-of-Use Assets The Company recorded an impairment loss of $34,169 and $0 for the twelve months ending December 31, 2020 and 2019, respectively. The loss related to a vacated portion of the facility that was no longer being subleased. The Company determined that the prolonged loss of sublease income and an adverse commercial real estate market caused by COVID-19 were indicators of impairment. A fair value approach using quoted prices for similar assets was used to determine the impairment loss. The loss was recorded within operating expenses in the statement of operations. The components of lease expense were as follows: Twelve Months Ended December 31, 2020 Twelve Months Ended December 31, 2019 Operating lease cost $ 441,529 $ 444,878 Operating sublease income (291,173) (381,653) Net operating lease cost $ 150,356 $ 63,225 Supplemental balance sheet information related to leases was as follows: As of December 31, 2020 As of December 31, 2019 Operating lease ROU assets $ 343,001 $ 697,418 Current operating lease liabilities $ 860,206 $ 865,379 Non-current operating lease liabilities 9,291 860,963 Total operating lease liabilities $ 869,497 $ 1,726,342 Weighted-average remaining lease term–operating leases 1.0 year 2.0 years Weighted-average discount rate–operating leases 6.5 % 6.5 % Supplemental cash flow and other information related to leases was as follows: Twelve Months Ended December 31, 2020 Twelve Months Ended December 31, 2019 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 943,959 $ 916,762 Total remaining annual commitments under non-cancelable lease agreements for each of the years ended December 31 are as follows: Year Ending December 31, Operating Leases Sublease Income Net Operating Leases 2021 $ 889,586 $ (403,345) $ 486,241 2022 5,868 — 5,868 2023 3,423 — 3,423 Total future minimum lease payments 898,877 $ (403,345) $ 495,532 Less imputed interest (29,380) Total $ 869,497
Leases	Leases As a lessee, the Company’s current leases include its master facility lease and immaterial equipment leases, all of which are considered operating leases. The Company (as a sublessor) also subleases portions of its facility to third parties under three separate subleases. All of these subleases have been determined to be operating leases and are accounted for separately from the head lease. Master Facility Lease The Company leases a building in San Diego under an operating lease that expires on December 31, 2021. The lease currently requires fixed monthly rent payments of approximately $78,000, with 3% annual escalation. Facility Subleases As a result of corporate restructurings in previous years, the Company vacated a portion of its facility and has subleased space to third parties under three separate sublease agreements, which all expire December 31, 2021. Income is recognized on a straight-line basis over the term of the sublease. Impairment of Right-of-Use Assets The Company recorded an impairment loss of $34,169 and $0 for the twelve months ending December 31, 2020 and 2019, respectively. The loss related to a vacated portion of the facility that was no longer being subleased. The Company determined that the prolonged loss of sublease income and an adverse commercial real estate market caused by COVID-19 were indicators of impairment. A fair value approach using quoted prices for similar assets was used to determine the impairment loss. The loss was recorded within operating expenses in the statement of operations. The components of lease expense were as follows: Twelve Months Ended December 31, 2020 Twelve Months Ended December 31, 2019 Operating lease cost $ 441,529 $ 444,878 Operating sublease income (291,173) (381,653) Net operating lease cost $ 150,356 $ 63,225 Supplemental balance sheet information related to leases was as follows: As of December 31, 2020 As of December 31, 2019 Operating lease ROU assets $ 343,001 $ 697,418 Current operating lease liabilities $ 860,206 $ 865,379 Non-current operating lease liabilities 9,291 860,963 Total operating lease liabilities $ 869,497 $ 1,726,342 Weighted-average remaining lease term–operating leases 1.0 year 2.0 years Weighted-average discount rate–operating leases 6.5 % 6.5 % Supplemental cash flow and other information related to leases was as follows: Twelve Months Ended December 31, 2020 Twelve Months Ended December 31, 2019 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 943,959 $ 916,762 Total remaining annual commitments under non-cancelable lease agreements for each of the years ended December 31 are as follows: Year Ending December 31, Operating Leases Sublease Income Net Operating Leases 2021 $ 889,586 $ (403,345) $ 486,241 2022 5,868 — 5,868 2023 3,423 — 3,423 Total future minimum lease payments 898,877 $ (403,345) $ 495,532 Less imputed interest (29,380) Total $ 869,497

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2020
Stockholders' Equity Note [Abstract]
Stockholders' Equity	Stockholders’ Equity Warrants A summary of warrant activity and changes in warrants outstanding, including both liability and equity classifications, is presented below: Number of Weighted-Average Weighted-Average Remaining Contractual Term Balance outstanding, December 31, 2018 3,649,341 $ 8.91 4.4 years Granted 7,437,454 $ 1.87 Exercised (497,313) $ 6.60 Balance outstanding, December 31, 2019 10,589,482 $ 4.08 3.7 years Granted 5,831,451 $ 1.70 Exercised (11,159,941) $ 2.31 Balance outstanding, December 31, 2020 5,260,992 $ 5.19 4.1 years The above table excludes pre-funded warrants with a nominal exercise price of $.01 per share: 1. 605,072 pre-funded warrants outstanding as of December 31, 2019; 2. 386,967 pre-funded warrants which were issued during the twelve months ending December 31, 2020; 3. All 992,039 pre-funded warrants were exercised in full during the twelve months ending December 31, 2020. Preferred Stock A summary of our Company's classes of preferred stock is presented below: Shares outstanding Class Par value Shares designated Liquidation preference As of December 31, 2020 As of December 31, 2019 Series A Convertible Preferred Stock $ 0.001 277,100 $ 606,000 60,600 60,600 Series B Convertible Preferred Stock $ 0.001 8,860 None — — Series C Convertible Preferred Stock $ 0.001 200,000 None — — Series D Convertible Preferred Stock $ 0.0001 154,670 None — — Series E Convertible Preferred Stock $ 0.001 865,824 None 655,044 — Series A Convertible Preferred Stock The material terms of the Series A Convertible Preferred Stock consist of: 1) Dividends. Holders of the Company’s Series A Convertible Preferred Stock are entitled to receive cumulative dividends at the rate per share of 4% per annum, payable quarterly on March 31, June 30, September 30 and December 31, beginning with September 30, 2005. Dividends are payable, at the Company’s sole election, in cash or shares of common stock. As of December 31, 2020 and 2019, the Company had $389,495 and $365,255, respectively in accrued cumulative unpaid preferred stock dividends, included in accrued liabilities in the Company’s balance sheets, and $24,240 and $24,240 of accrued dividends were recorded during the years ended December 31, 2020 and 2019, respectively. 2) Voting Rights. Shares of the Series A Convertible Preferred Stock have no voting rights. However, so long as any shares of Series A Convertible Preferred Stock are outstanding, the Company may not, without the affirmative vote of the holders of the shares of Series A Convertible Preferred Stock then outstanding, (a) adversely change the powers, preferences or rights given to the Series A Convertible Preferred Stock, (b) authorize or create any class of stock senior or equal to the Series A Convertible Preferred Stock, (c) amend its certificate of incorporation or other charter documents, so as to affect adversely any rights of the holders of Series A Convertible Preferred Stock or (d) increase the authorized number of shares of Series A Convertible Preferred Stock. 3) Liquidation. Upon any liquidation, dissolution or winding-up of the Company, the holders of the Series A Convertible Preferred Stock are entitled to receive an amount equal to the Stated Value per share, which is currently $10 per share plus any accrued and unpaid dividends. 4) Conversion Rights. Each share of Series A Convertible Preferred Stock is convertible at the option of the holder into that number of shares of common stock determined by dividing the Stated Value, currently $10 per share, by the conversion price, which at the time of issuance was $928.80 per share, and subsequently adjusted to $691.20 per share. 5) Subsequent Equity Sales. The conversion price is subject to adjustment for dilutive issuances for a period of 12 months beginning upon registration of the common stock underlying the Series A Convertible Preferred Stock. The relevant registration statement became effective on March 17, 2006 and the conversion price was adjusted to $691.20 per share. 6) Automatic Conversion. If the price of the Company’s common stock equals $1,857.60 per share for 20 consecutive trading days, and an average of 116 shares of common stock per day are traded during the 20 trading days, the Company will have the right to deliver a notice to the holders of the Series A Convertible Preferred Stock, requesting the holders to convert any portion of the shares of Series A Convertible Preferred Stock into shares of common stock at the applicable conversion price. As of the date of these financial statements, such conditions have not been met. Series C Convertible Preferred Stock and Service Receivable On January 25, 2019, the Company entered into a Master Services Agreement and a Stock and Warrant Subscription Agreement with PoC Capital, LLC (“PoC”), whereby PoC agreed to finance $1.675 million for the development costs associated with Phase 1b/2 study of onvansertib in combination with FOLFIRI and Avastin ® in patients with metastatic Colorectal Cancer (“mCRC”) harboring KRAS mutation in exchange for (i)183,334 shares of common stock, (ii) warrants to purchase an aggregate of 150,000 shares of common stock, with an exercise price of $3.762 per share, expiring on January 25, 2024, and (iii) 200,000 shares of Series C Convertible Preferred Stock, each share of which was convertible into 1.67 shares of common stock. In April of 2019, all 200,000 shares of Series C Convertible Preferred Stock were converted into 333,333 shares of the Company's common stock. The Company evaluated the awards issued under this transaction and determined they should be classified as equity. These equity awards were fully vested and non-forfeitable. Since the equity awards were for clinical trial services yet to be provided, the Company recognized $1.675 million service receivables as contra equity. The Company releases the service receivables as clinical trial services are performed. The conversion feature of the Series C Convertible Preferred Stock at the time of issuance was determined to be beneficial on the commitment date. Because the Series C Convertible Preferred Stock was perpetual with no stated maturity date, and the conversions could occur any time from inception, the Company immediately recorded a non-cash deemed dividend of $0.3 million related to the beneficial conversion feature arising from the issuance of Series C Convertible Preferred Stock. This non-cash deemed dividend increased the Company’s net loss attributable to common stockholders and net loss per share. Series D Convertible Preferred Stock and Service Receivable On May 8, 2020, the Company entered into a Stock and Warrant Subscription Agreement with PoC, whereby PoC agreed to finance an additional $2.3 million for a clinical trial in exchange for (i) 602,833 shares of its common stock (the “Common Stock”), (ii) 154,670 shares of its Series D Preferred Stock and (iii) a warrant exercisable for 859,813 shares of its Common Stock. In exchange, PoC is funding our clinical development of onvansertib in metastatic colorectal cancer pursuant to a Master Services Agreement dated as of January 25, 2019, as amended. The warrant will be exercisable six months following the date of issuance at an exercise price of $1.50 per share and will expire on November 7, 2025. In June of 2020, all 154,670 Series D Preferred Stock were converted to 1,546,700 shares of Common Stock. The Company evaluated the awards issued under this transaction and determined they should be classified as equity. These equity awards were fully vested and non-forfeitable. Since the equity awards were for clinical trial services yet to be provided, the Company recognized $2.3 million service receivables as contra equity. The Company releases the service receivables as clinical trial services are performed. The conversion feature of the Series D Convertible Preferred Stock at the time of issuance was determined to be beneficial on the commitment date. Because the Series D Convertible Preferred Stock was perpetual with no stated maturity date, and the conversions could occur any time from inception, the Company immediately recorded a non-cash deemed dividend of $0.6 million related to the beneficial conversion feature arising from the issuance of Series D Convertible Preferred Stock. This non-cash deemed dividend increased the Company’s net loss attributable to common stockholders and net loss per share. Series E Convertible Preferred Stock On June 15, 2020 the Company entered into a Securities Purchase Agreement with Acorn Bioventures LP ("Acorn"), CDK Associates, L.L.C. (“CDK”) and Third Street Holdings LLC (“Third Street”), pursuant to which the Company agreed to offer, issue and sell to Acorn, CDK and Third Street, (i) in a registered direct offering, an aggregate of 1,984,328 shares of common stock and (ii) in a concurrent private placement, (a) an aggregate of 865,824 shares of Series E Preferred Stock (“Series E Preferred Stock”) and (b) Series N warrants to purchase up to 2,213,115 shares of Common Stock. The Series E Preferred Stock is convertible at any time determined by dividing the $10 stated value per share of the Series E Preferred Stock by a conversion price of $2.44 per share, subject to adjustment in accordance with the Certificate of Designation. The Series N Warrants will be exercisable six months following the date of issuance at an exercise price of $2.39 per share and will expire on December 16, 2025. Certain investors converted 210,780 shares of Series E Convertible Preferred stock to 863,852 shares of Common Stock during December 2020. The conversion feature of the Series E Convertible Preferred Stock at the time of issuance was determined to be beneficial on the commitment date. Because the Series E Convertible Preferred Stock was perpetual with no stated maturity date, and the conversions could occur any time from inception, the Company immediately recorded a non-cash deemed dividend of $2.7 million related to the beneficial conversion feature arising from the issuance of Series E Convertible Preferred Stock. This non-cash deemed dividend increased the Company’s net loss attributable to common stockholders and net loss per share. In conjunction with the June 15, 2020 offering, we issued 184,426 warrants as an advisory fee. These warrants are exercisable six months following the date of issuance at an exercise price of $3.05 per share and will expire 5.5 years following the date of issuance. These warrants are classified as equity and its estimated fair value of $370,666 was recognized as additional paid in capital on the issuance date. The estimated fair value is determined using the Black-Scholes Option Pricing Model which is based on the value of the underlying common stock at the valuation measurement date, the remaining contractual term of the warrant, risk-free interest rates, expected dividends and expected volatility of the price of the underlying common stock. Securities Purchase Agreements with Lincoln Park Capital Fund, LLC On March 30, 2020, the Company entered into a Securities Purchase Agreement with Lincoln Park Capital Fund, LLC (“LPC”), pursuant to which the Company agreed to offer, issue and sell to LPC, (i) in a registered direct offering, an aggregate of (a) 800,000 shares of common stock and (b) Series I warrants to purchase up to 131,967 shares (the “Series I Warrant Shares”) of common stock. In a concurrent private placement, the Company also sold to LPC Series J warrants (the “Series J Warrants”) to purchase one share of common stock for each Share and for each Series I Warrant purchased for cash in the registered direct offering. The Series J Warrants are exercisable six months following the date of issuance at an exercise price of $0.948 per share and will expire 5.5 years following the date of issuance. The gross proceeds from this purchase were $1.0 million. On April 9, 2020, the Company entered into a Securities Purchase Agreement with LPC, pursuant to which the Company agreed to offer, issue and sell to LPC, (i) in a registered direct offering, an aggregate of (a) 904,970 shares of common stock and (b) Series K warrants to purchase up to 255,000 shares (the “Series K Warrant Shares”) of common stock. In a concurrent private placement, the Company also sold to LPC Series L warrants (the “Series L Warrants”) to purchase one share of Common Stock for each Share and for each Series K Warrant purchased for cash in the registered direct offering. The Series L Warrants are exercisable six months following the date of issuance at an exercise price of $0.81 per share and will expire 5.5 years following the date of issuance. The gross proceeds from this purchase were $1.1 million. Securities Purchase Agreement with Certain Directors and Executives On May 11, 2020 and May 14, 2020, the Company entered into Securities Purchase Agreements with certain directors and executives of the Company pursuant to which the Company sold 447,761 shares of common stock at a purchase price of $1.34 per share and 146,854 shares of common stock at a purchase price of $1.43 per share. The gross proceeds from these purchases were $810,000. Securities Purchase Agreement with Acorn Bioventures LP On May 26, 2020, the Company entered into a Securities Purchase Agreement with Acorn, pursuant to which the Company agreed to offer, issue and sell to Acorn, (i) in a registered direct offering, an aggregate of 1,205,400 shares of common stock and (ii) in a concurrent private placement, Series M warrants to purchase up to 482,160 shares of common stock. The Series M Warrants are exercisable six months following the date of issuance at an exercise price of $2.024 per share and will expire 5.5 years following the date of issuance. The gross proceeds from this purchase were $2.5 million. Underwritten Public Offering

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2020
Share-based Payment Arrangement [Abstract]
Stock-Based Compensation	Stock-Based Compensation The Cardiff Oncology, Inc. 2014 Equity Incentive Plan (the “2014 EIP”), authorizing up to 34,722 shares of common stock for issuance under the 2014 EIP, was approved by the Board in June 2014 and approved by the stockholders of the Company at the September 17, 2014 Annual Meeting of Stockholders. The total number of authorized shares was increased to 243,056 between the inception of the 2014 EIP through December 31, 2018. At the June 6, 2019 Annual Meeting of Stockholders, the stockholders approved the increase of number of authorized shares in the 2014 EIP to 1,243,056. At the April 6, 2020 Annual meeting of Stockholders, the stockholders approved the increase of number of authorized shares in the 2014 EIP to 2,243,056 As of December 31, 2020, there were 260,446 shares available for issuance under the 2014 EIP. Stock-based compensation has been recognized in operating results as follows: Years ended December 31, 2020 2019 Research and development expenses 354,692 399,687 Selling, general and administrative expenses 1,410,112 485,256 Total stock-based compensation $ 1,764,804 $ 884,943 Stock Options The estimated fair value of stock option awards was determined on the date of grant using the Black-Scholes option valuation model with the following assumptions during the years indicated below: Years ended December 31, 2020 2019 Risk-free interest rate 0.39% - 0.93% 1.66% - 2.33% Dividend yield 0% 0% Expected volatility (range) 102% - 106% 95% - 99% Expected volatility (weighted-average) 105% 96% Expected term (in years) 5.9 years 5.9 years Risk-free interest rate — Based on the daily yield curve rates for U.S. Treasury obligations with maturities that correspond to the expected term of the Company’s stock options. Dividend yield — Cardiff Oncology has not paid any dividends on common stock since its inception and does not anticipate paying dividends on its common stock in the foreseeable future. Expected volatility — Based on the historical volatility of Cardiff Oncology’s common stock. Expected term — The expected option term represents the period that stock-based awards are expected to be outstanding based on the simplified method, which averages an award’s weighted-average vesting period and expected term for “plain vanilla” share options. Options are considered to be “plain vanilla” if they have the following basic characteristics: (1) are granted “at-the-money”; (2) exercisability is conditioned upon service through the vesting date; (3) termination of service prior to vesting results in forfeiture; (4) limited exercise period following termination of service; and (5) are non-transferable and non-hedgeable. Forfeitures — The Company estimates forfeitures based on its historical experience. The weighted-average fair value per share of all options granted during the years ended December 31, 2020 and 2019, estimated as of the grant date using the Black-Scholes option valuation model, was $2.09 and $1.91 per share, respectively. The unrecognized compensation cost related to non-vested stock options outstanding at December 31, 2020 was $1,519,004. The weighted-average remaining amortization period at December 31, 2020 for non-vested stock options was 1.9 years. The total fair value of shares vested during the years ended December 31, 2020 and 2019 was $1,522,984 and $386,654, respectively. The intrinsic value of stock options exercised during the year ended December 31, 2019 was $0. A summary of stock option activity and of changes in stock options outstanding is presented below: Number of Options Weighted-Average Exercise Price Per Share Intrinsic Weighted-Average Balance outstanding, December 31, 2019 1,015,418 $ 12.77 $ — 9.1 years Granted 969,965 $ 2.53 Exercised (60,195) $ 2.46 $ 970,145 Forfeited (48,537) $ 22.91 Expired (16,144) $ 21.29 Balance outstanding, December 31, 2020 1,860,507 $ 7.43 $ 27,963,363 8.9 years Vested and exercisable, December 31, 2020 753,206 $ 14.63 $ 10,837,211 8.5 years Vested and expected to vest, December 31, 2020 1,777,407 $ 7.65 $ 26,682,849 8.9 years Restricted Stock Units RSU's are measured at the grant date based on the closing market price of the Company’s common stock at the grant date and recognized ratably over the service period through the vesting date. All RSU's were granted with no purchase price. Vesting of the RSU's is generally subject to service conditions. A summary of the RSU's activity is presented below: Number of Shares Weighted Average Intrinsic Non-vested RSU's outstanding, December 31, 2018 30,132 $ 14.36 $ 95,005 Granted 9,167 $ 1.61 Vested (22,057) $ 8.68 Forfeited (5,941) $ 13.82 Non-vested RSU's outstanding, December 31, 2019 11,301 $ 15.38 $ 14,013 Vested (10,810) $ 9.37 Non-vested RSU's outstanding, December 31, 2020 491 $ 147.60 $ 7,641

Derivative Financial Instrument

Derivative Financial Instruments - Warrants	12 Months Ended
	Dec. 31, 2020
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Financial Instruments - Warrants	Derivative Financial Instruments — Warrants Certain warrants issued in connection with the Company’s equity financings are accounted for as derivative liabilities. Accordingly, the warrants are remeasured at each balance sheet date based on their estimated fair value using the Black-Scholes option pricing model. Changes in fair value are recorded within Company’s statements of operations. The range of assumptions used to determine the fair value of the warrants valued using the Black-Scholes option pricing model during the periods indicated was: Year ended December 31, 2020 2019 Fair value of Cardiff Oncology common stock $1.01 - $17.99 $1.24 - $3.75 Expected warrant term 2.1 - 3.1 years 3.1 - 4.1 years Risk-free interest rate 0.13% - 1.62% 1.56% - 2.49% Expected volatility 110% - 118% 102% - 111% Dividend yield —% —% As of December 31, 2020 Weighted Average (1)(2) : Fair value of Cardiff Oncology common stock $17.99 Expected warrant term 2.1 years Risk-free interest rate 0.13 % Expected volatility of Cardiff Oncology common stock 116 % Dividend yield 0 % (1) Weighted average is only disclosed for periods after January 1, 2020 under the adoption of ASU 2018-13. (2) The weighted average was calculated using the relative fair value method. Expected volatility is based on the historical volatility of Cardiff Oncology’s common stock. The warrants have a transferability provision and based on guidance for instruments issued with such a provision, Cardiff Oncology used the remaining contractual term as the expected term of the warrants. The risk-free interest rate is based on the U.S. Treasury security rates consistent with the expected remaining term of the warrants at each balance sheet date. The following table sets forth the components of changes in the Company’s derivative financial instruments — warrants liability balance, valued using the Black-Scholes option pricing method, for the periods indicated. Date Description Number of Warrants Derivative December 31, 2018 Balance of derivative financial instruments — warrants liability 64,496 $ 32,315 Change in fair value of derivative financial instruments — warrants during the year recognized as a gain in the statement of operations — (28,188) December 31, 2019 Balance of derivative financial instruments — warrants liability 64,496 4,127 Change in fair value of derivative financial instruments — warrants during the year recognized as a loss in the statement of operations — 280,844 December 31, 2020 Balance of derivative financial instruments — warrants liability 64,496 $ 284,971 The remaining contractual term of the warrants outstanding at December 31, 2020 and 2019 was approximately 2.1 and 3.1 years, respectively.

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2020
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements The following table presents the Company’s assets and liabilities that are measured and recognized at fair value on a recurring basis classified under the appropriate level of the fair value hierarchy as of December 31, 2020 and 2019: Fair Value Measurements at Quoted Prices in Active Markets for Identical Assets and Liabilities Significant Other Observable Inputs Significant Unobservable Inputs Total Assets: Money market fund (1) $ 129,987,804 $ — $ — $ 129,987,804 Total Assets $ 129,987,804 $ — $ — $ 129,987,804 Liabilities: Derivative financial instruments — warrants $ — $ — $ 284,971 $ 284,971 Total Liabilities $ — $ — $ 284,971 $ 284,971 Fair Value Measurements at Quoted Prices in Active Markets for Identical Assets and Liabilities Significant Other Observable Inputs Significant Unobservable Inputs Total Assets: Money market fund (1) $ 10,131,240 $ — $ — $ 10,131,240 Total Assets $ 10,131,240 $ — $ — $ 10,131,240 Liabilities: Derivative financial instruments — warrants $ — $ — $ 4,127 $ 4,127 Total Liabilities $ — $ — $ 4,127 $ 4,127 (1) Included as a component of cash and cash equivalents on the accompanying balance sheet. The change in the fair value of the “derivative financial instruments—warrants” is recorded as a gain or loss in the Company’s statement of operations. A financial instrument’s level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement. At each reporting period, the Company reviews the assets and liabilities that are subject to ASC Topic 815-40 and ASC Topic 480-10. At each reporting period, all assets and liabilities for which the fair value measurement is based on significant unobservable inputs or instruments that trade infrequently and therefore have little or no price transparency are classified as Level 3.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes At December 31, 2020, Cardiff Oncology had federal net operating loss carryforwards (“NOLs”) of approximately $128.9 million which, if not used, will continue to expire through 2037, and federal net operating loss carryforwards of approximately $48.4 million, which do not expire. Cardiff Oncology also has California NOLs of approximately $70.7 million which, if not used, will begin to expire in 2029. Cardiff Oncology has Federal and California capital loss carryforwards of $0.7 million which, if not used, will begin to expire in 2022. Cardiff Oncology also has research and development tax credits available for federal and California purposes of approximately $2.5 million and $1.8 million, respectively. The federal research and development tax credits will begin to expire on January 31, 2025. The California research and development tax credits do not expire. Pursuant to the Internal Revenue Code of 1986, as amended (the “Code”) Sections 382 and 383, annual use of a company’s NOL and research and development credit carryforwards may be limited if there is a cumulative change in ownership of greater than 50% within a three-year period. The amount of the annual limitation is determined based on the value of the Company immediately prior to the ownership change. Subsequent ownership changes may further affect the limitation in future years. If limited, the related tax asset would be removed from the deferred tax asset schedule with a corresponding reduction in the valuation allowance. The Company has not completed such an analysis pursuant to Sections 382 and 383 and therefore has established a valuation allowance as the realization of such deferred tax assets has not met the more likely than not threshold requirement. Due to the existence of the valuation allowance, further changes in the Company’s unrecognized tax benefits will not impact the Company’s effective tax rate. The provision for income taxes based on losses from continuing operations consists of the following at December 31 (in thousands): Years ended December 31, 2020 2019 Current: State $ 1 $ 1 Total current provision 1 1 Deferred: Federal (4,043) (2,634) State (92) (148) Total deferred (benefit) expense (4,135) (2,782) Valuation allowance 4,134 2,781 Total income tax provision $ — $ — Significant components of the Company’s taxes and the rates as of December 31 are shown below (in thousands, except percentages): Years ended December 31, 2020 2019 Tax computed at the federal statutory rate $ (4,054) 21 % $ (3,447) 21 % State tax, net of federal tax benefit (122) 1 % (177) 1 % Permanent Items 261 (1) % 353 (2) % Stock options true-up 81 (1) % 875 (5) % Tax credits (300) 2 % (384) 2 % Valuation allowance increase (decrease) 4,134 (22) % 2,780 (17) % Provision for income taxes $ — — % $ — — % Significant components of the Company’s deferred tax assets and liabilities from federal and state income taxes as of December 31 are shown below (in thousands): Years ended December 31, 2020 2019 Deferred tax assets: Tax loss carryforwards $ 42,331 $ 38,494 Research and development credits and other tax credits 3,904 3,710 Stock-based compensation 684 531 Other 1,116 1,252 Total deferred tax assets 48,035 43,987 Deferred tax liabilities: Operating lease right-of-use assets (74) (154) Other (6) (12) Total deferred tax liabilities (80) (166) Net deferred tax assets before valuation allowance 47,955 43,821 Valuation allowance (47,955) (43,821) Net deferred tax asset $ — $ — Since inception the Company has incurred continuing losses and expects to continue to incur losses for the foreseeable future. The Company has recorded a full valuation allowance against its net deferred tax assets as it is more likely than not they will not be realized. Cardiff Oncology does not have any unrecognized tax benefits. Cardiff Oncology’s practice is to recognize interest and/or penalties related to income tax matters in income tax expense, and none have been incurred to date. The Company does not anticipate a significant change in unrecognized tax benefits over the next 12 months. The Company is subject to taxation in the U.S. and California. Due to net operating losses all tax years since inception remain open to examination.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Executive Agreements Certain executive agreements provide for severance payments in case of terminations without cause or certain change of control scenarios. Research and Development and Clinical Trial Agreements In March 2017, the Company entered into a license agreement with Nerviano which granted the Company development and commercialization rights to NMS-1286937, which Cardiff Oncology refers to as onvansertib. Onvansertib is an oral, investigative drug and a highly-selective adenosine triphosphate competitive inhibitor of the serine/threonine PLK1. The Company plans to develop onvansertib in patients with leukemias/lymphomas and solid tumor cancers. Upon execution of the agreement, the Company paid $2.0 million in license fees which were expensed to research and development costs. The Company was committed to order $1.0 million of future services provided by Nerviano, such as the cost to manufacture drug product, no later than June 30, 2019, and these services have been purchased. Terms of the agreement also provide for the Company to pay development milestones and royalties based on sales volume. The Company is a party to various agreements under which it licenses technology on an exclusive basis in the field of human diagnostics and oncology therapeutics. License fees are generally calculated as a percentage of product revenues, with rates that vary by agreement. To date, payments have not been material. Litigation Cardiff Oncology does not believe that it has legal liabilities that are probable or reasonably possible that require either accrual or disclosure. From time to time, the Company may become involved in various lawsuits and legal proceedings that arise in the ordinary course of business. Litigation is subject to inherent uncertainties, and an adverse result in matters may arise

Employee Benefit Plan

Employee Benefit Plan	12 Months Ended
	Dec. 31, 2020
Retirement Benefits [Abstract]
Employee Benefit Plan	Employee Benefit Plan The Company has a defined contribution retirement plan under Section 401(k) of the Internal Revenue Service ("IRS") Code covering its employees. The plan allows employees to defer, up to the maximum allowed, a percentage of their income through contributions to the plan as allowed by IRS Code. The Company does not currently make matching contributions.

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2020
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions Leucadia Life Sciences In November 2018, the Company entered into a Material Transfer Agreement (“MTA”) with Leucadia Life Sciences (“Leucadia”) pursuant to which Leucadia will develop a PCR-based assay for onvansertib for Acute Myeloid Leukemia (“AML”). One of the Company’s Directors, Dr. Thomas Adams, is a principal stockholder of Leucadia. In connection with the MTA, the Company entered into a consulting agreement with Tommy Adams, Co-Founder & Chief Operating Officer of Leucadia, who is the son of Dr. Adams. During the years ended December 31, 2020 and 2019, the Company incurred and recorded approximately $1,083,000 and $1,005,000, respectively, of research and development expenses for services performed by Leucadia and Tommy Adams. The assay was completed in December 2020. Gary Pace Securities Purchase Agreement

COVID-19

COVID-19	12 Months Ended
	Dec. 31, 2020
Unusual or Infrequent Items, or Both [Abstract]
COVID-19	COVID-19 The COVID-19 outbreak in the United States has caused significant business disruption. The extent of the impact of COVID-19 on the Company's future operational and financial performance will depend on certain developments, including the duration and spread of the outbreak, and impact on the Company's clinical trials, employees and vendors, all of which are uncertain and cannot be predicted. At this point, the extent to which COVID-19 may impact the Company's future financial condition or results of operations is uncertain. While there has not been a material impact on the Company's financial statements for the twelve months ended December 31, 2020, a prolonged outbreak could have a material adverse impact on financial results and business operations of the Company, including the timing and ability of the Company to complete certain clinical trials and other efforts required to advance the development of its drugs and raise additional capital. In response to the pandemic, the Coronavirus Aid, Relief and Economic Security Act (“CARES Act”) was signed into law on March 27, 2020. The CARES Act, among other things, includes tax provisions relating to refundable payroll tax credits, deferment of employer’s social security payments, net operating loss utilization and carryback periods, modifications to the net interest deduction limitations and technical corrections to tax depreciation methods for qualified improvement property. The Company is utilizing the deferment of employer social security payments. The CARES Act did not have a material impact on our income tax provision for the twelve months ended December 31, 2020. We continue to monitor changes and revisions of the CARES Act and its impact on our financial position, results of operations and cash flows. Repayment of Small Business Administration Payroll Protection Program Loan On April 15, 2020, the Company was granted a loan (the “Loan”) from JPMorgan Chase Bank, N.A. in the aggregate amount of $305,000, pursuant to the Paycheck Protection Program (the “PPP”) under Division A, Title I of the CARES Act with an interest rate of 0.98% per annum. On October 19, 2020 the Company repaid in full the outstanding principal and interest of the PPP Loan.

Basis of Presentation and Sum_2

Basis of Presentation and Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Segment Reporting	Segment Reporting Operating segments are identified as components of an enterprise about which separate discrete financial information is available for evaluation by the chief operating decision-maker in making decisions regarding resource allocation and assessing performance. The Company views its operations as, and manages its business in, one operating segment.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make significant estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. The most significant estimates involve accrued clinical trial expenses and determining the assumptions made for stock-based compensation.
Accrued Clinical Trial Expenses	Accrued Clinical Trial Expenses The Company expenses research and development expenditures as incurred, which include costs related to clinical trial activities. The Company accrues costs for clinical trial activities based upon estimates of the services received and related expenses incurred that have yet to be invoiced by the clinical research organizations (CROs), investigators, professional service providers, and other vendors providing clinical trial services (collectively, the “service providers”). As of December 31, 2020 the Company’s Clinical trial accrual balance of $1,683,195 is included in accrued liabilities and other liabilities. The Company’s related 2020 clinical trial expenses are included in research and development expense of $11,235,396. Certain accrued clinical trial expenses are released from service receivables classified within equity (see Note 5) as clinical trial services are performed.
Cash and Cash Equivalents	Cash and Cash Equivalents
Concentration of Credit Risk	Concentration of Credit Risk Financial instruments that potentially subject the Company to significant concentrations of credit risk consist primarily of cash and cash equivalents. The Company maintains deposit accounts at financial institutions that are in excess of federally insured limits. The Company has not experienced any losses in such accounts and believes it is not exposed to significant risk on its cash due to the financial position of the depository institution in which those deposits are held. The Company limits its exposure to credit loss by generally placing its cash in high credit quality financial institutions and investment in non FDIC insured money market funds denominated and payable in U.S. dollars. Additionally, the Company has established guidelines regarding diversification of its investments and their maturities, which are designed to maintain principal and maximize liquidity.
Revenues	Revenues The Company recognizes revenue when control of its products and services are transferred to its customers in an amount that reflects the consideration it expects to receive from its customers in exchange for those products and services. This process involves identifying the contract with a customer, determining the performance obligations in the contract, determining the contract price, allocating the contract price to the distinct performance obligations in the contract, and recognizing revenue when the performance obligations have been satisfied. A performance obligation is considered distinct from other obligations in a contract when it provides a benefit to the customer either on its own or together with other resources that are readily available to the customer and is separately identified in the contract. The Company considers a performance obligation satisfied once it has transferred control of goods or service to the customer, meaning the customer has the ability to use and obtain the benefit of goods or service. The Company recognizes revenue for satisfied performance obligations only when it determines there are no uncertainties regarding payment terms or transfer of control. For sales-based royalties, the Company recognizes 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). Royalty and License Revenues The Company licenses and sublicenses its patent rights to healthcare companies, medical laboratories and biotechnology partners. These agreements may involve multiple elements such as license fees, royalties and milestone payments. Revenue is recognized when the criteria described above have been met as well as the following: • Up-front nonrefundable license fees pursuant to agreements under which the Company has no continuing performance obligations are recognized as revenues on the effective date of the agreement and when collection is probable. • Minimum royalties are recognized as earned, and royalties are earned based on the licensee’s use. The Company estimates and records licensee’s sales based on historical usage rate and collectability. • For sales-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).
Derivative Financial Instruments—Warrants	Derivative Financial Instruments—Warrants The Company has issued common stock warrants in connection with the execution of certain equity financings. Such warrants are classified as derivative liabilities and are recorded at their fair market value as of each reporting period. Such warrants do not meet the exemption that a contract should not be considered a derivative instrument if it is (1) indexed to its own stock and (2) classified in stockholders’ equity. The warrants contain a feature that could require the transfer of cash in the event a change of control occurs without an authorization of the Company’s Board of Directors, and therefore classified as a liability. Changes in fair value of derivative liabilities are recorded in the statement of operations under the caption “Change in fair value of derivative instruments — warrants.” The fair value of warrants is determined using the Black-Scholes option-pricing model using assumptions regarding the historical volatility of Cardiff Oncology’s common stock price, the remaining life of the warrants, and the risk-free interest rates at each period end. The Company thus uses model-derived valuations where inputs are observable in active markets to determine the fair value. The use of the Black-Scholes model classifies such warrants as Level 3 (See " Fair Value of Financial Instruments"
Stock-Based Compensation	Stock-Based Compensation Stock-based compensation expense is measured at the grant date based on the estimated fair value of the award and is recognized straight-line over the requisite service period of the individual grants, which typically equals the vesting period.
Fair Value of Financial Instruments	Fair Value of Financial Instruments Financial instruments consist of cash equivalents, accounts receivable, accounts payable and derivative liabilities. The Company applies ASC 820 for financial assets and liabilities that are required to be measured at fair value and non-financial assets and liabilities that are not required to be measured at fair value on a recurring basis. These financial instruments are stated at their respective historical carrying amounts, which approximate fair value due to their short-term nature as they reflect current market interest rates. The authoritative guidance establishes a fair value hierarchy that is based on the extent and level of judgment used to estimate the fair value of assets and liabilities. In general, the authoritative guidance requires us to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. An asset or liability’s categorization within the fair value hierarchy is based upon the lowest level of input that is significant to the measurement of its fair value. The three levels of input defined by the authoritative guidance are as follows: The Company measures certain assets and liabilities at fair value on a recurring basis using the three-tier fair value hierarchy, which prioritizes the inputs used in measuring fair value. The three tiers include: • Level 1 — Quoted prices for identical instruments in active markets. • Level 2 — Quoted prices for similar instruments in active markets; quoted prices for identical or similar instruments in markets that are not active; and model-derived valuations where inputs are observable or where significant value drivers are observable. • Level 3 — Instruments where significant value drivers are unobservable to third parties.
Long-Lived Assets	Long-Lived Assets three
Impairment Losses on Long-Lived Assets	Impairment losses on long-lived assets used in operations are recorded when indicators of impairment are present and the undiscounted cash flows estimated to be generated by those assets are less than the assets carrying amount. If such assets are considered to be impaired, the impairment to be recognized is measured by the amount by which the carrying amount of the assets exceeds the estimated fair value of the assets.
Leases	Leases The Company determines if an arrangement is a lease at inception. Operating leases are included in operating lease right-of-use (“ROU”) assets, current operating lease liabilities and non-current operating lease liabilities in the Company’s balance sheets. ROU assets represent the Company’s right to use an underlying asset for the lease term and lease liabilities represent its obligation to make lease payments arising from the lease. Operating lease ROU assets and liabilities are recognized at commencement date based on the present value of lease payments over the lease term. As most of the Company’s operating leases do not provide an implicit rate, the Company uses its incremental borrowing rate based on the information available at commencement date in determining the present value of lease payments. The incremental borrowing rate is the rate of interest that the Company would expect to pay to borrow on a collateralized and fully amortizing basis over a similar term an amount equal to the lease payments in a similar economic environment. The operating lease ROU asset also includes any lease payments made less lease incentives received. The Company’s lease terms may include options to extend or terminate the lease when it is reasonably certain that the Company will exercise that option. Lease expense is recognized on a straight-line basis over the lease term. Our facilities lease agreement contains lease and non-lease components, such as common area maintenance. We have elected to account for these lease and non-lease components of this agreement as a single lease component.
Income Taxes	Income Taxes Income taxes are determined using the asset and liability approach of accounting for income taxes. Under this approach, deferred taxes represent the future tax consequences expected to occur when the reported amounts of assets and liabilities are recovered or paid. Deferred taxes result from differences between the financial statement and tax bases of Cardiff Oncology’s assets and liabilities and are adjusted for changes in tax rates and tax laws when changes are enacted. Valuation allowances are recorded to reduce deferred tax assets when it is more likely than not that a tax benefit will not be realized. The assessment of whether or not a valuation allowance is required often requires significant judgment.
Contingencies	Contingencies In the normal course of business, Cardiff Oncology is subject to loss contingencies, such as legal proceedings and claims arising out of its business, that cover a wide range of matters, including, among others, government investigations, stockholder lawsuits, product and environmental liability, and tax matters. In accordance with FASB ASC Topic 450, Contingencies , Cardiff Oncology records such loss contingencies when it is probable that a liability has been incurred and the amount of loss can be reasonably estimated. Cardiff Oncology, in accordance with this guidance, does not recognize gain contingencies until realized.
Research and Development	Research and Development Research and development expenses include expenditures in connection with an in-house research and development laboratory, salaries and staff costs, clinical trials, purchased in-process research and development and regulatory and scientific consulting fees, as well as contract research and insurance. Also, patent filing and maintenance expenses are considered legal in nature and therefore classified as general and administrative expense, if any.
Net Loss Per Share	Net Loss Per Share
Recently Adopted Accounting Pronouncement	Recently Adopted Accounting Pronouncement In August 2018, the FASB issued ASU No. 2018-13 ("ASU 2018-13"), Changes to the Disclosure Requirements for Fair Value Measurement . This ASU eliminates, adds and modifies certain disclosure requirements for fair value measurements as part of its disclosure framework project. The standard is effective for all entities for financial statements issued for fiscal years beginning after December 15, 2019, and interim periods within those fiscal years. The Company has prospectively adopted ASU 2018-13 as of January 1, 2020 for periods presented after adoption. The adoption of ASU 2018-13 did not have a material impact on the Company's financial statements. In August 2020, the FASB issued ASU No. 2020-06 ("ASU 2020-06"), Debt - Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging - Contracts in Entity’s Own Equity (Subtopic 815-40) (“ASU 2020-06”)

Basis of Presentation and Sum_3

Basis of Presentation and Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Schedule of Antidilutive Securities Excluded from the Calculation of Basic and Diluted Loss Per Share	Shares used in calculating diluted net loss per common share exclude as anti-dilutive the following share equivalents: December 31, 2020 2019 Options to purchase Common Stock 1,860,507 1,015,418 Warrants to purchase Common Stock 5,260,992 10,589,482 Restricted Stock Units 491 11,301 Series A Convertible Preferred Stock 877 877 Series E Convertible Preferred Stock 2,684,607 — 9,807,474 11,617,078

Supplementary Balance Sheet I_2

Supplementary Balance Sheet Information (Tables)	12 Months Ended
	Dec. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Components of Property and Equipment	Property and equipment consisted of the following: As of December 31, 2020 2019 Furniture and office equipment $ 797,739 $ 775,030 Leasehold improvements 1,962,230 1,962,230 Laboratory equipment 867,750 744,856 3,627,719 3,482,116 Less—accumulated depreciation (3,004,025) (2,604,293) Property and equipment, net $ 623,694 $ 877,823
Components of Accrued Liabilities	Accrued liabilities consisted of the following: As of December 31, 2020 2019 Accrued compensation $ 1,523,321 $ 1,003,383 Preferred stock dividend 389,495 365,255 Clinical trials 1,557,134 1,504,660 Research agreements and services 66,593 181,408 Director fees 92,500 67,500 Professional fees and outside services 38,180 21,000 Patent, license and other fees 117,440 69,950 Other accrued liabilities 66,100 46,905 Total accrued liabilities $ 3,850,763 $ 3,260,061

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2020
Leases [Abstract]
Summary of Lease Expense and Supplemental Cash Flow Information	The components of lease expense were as follows: Twelve Months Ended December 31, 2020 Twelve Months Ended December 31, 2019 Operating lease cost $ 441,529 $ 444,878 Operating sublease income (291,173) (381,653) Net operating lease cost $ 150,356 $ 63,225 Supplemental cash flow and other information related to leases was as follows: Twelve Months Ended December 31, 2020 Twelve Months Ended December 31, 2019 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 943,959 $ 916,762
Supplemental Balance Sheet Information	Supplemental balance sheet information related to leases was as follows: As of December 31, 2020 As of December 31, 2019 Operating lease ROU assets $ 343,001 $ 697,418 Current operating lease liabilities $ 860,206 $ 865,379 Non-current operating lease liabilities 9,291 860,963 Total operating lease liabilities $ 869,497 $ 1,726,342 Weighted-average remaining lease term–operating leases 1.0 year 2.0 years Weighted-average discount rate–operating leases 6.5 % 6.5 %
Summary of Future Minimum Lease Payments	Total remaining annual commitments under non-cancelable lease agreements for each of the years ended December 31 are as follows: Year Ending December 31, Operating Leases Sublease Income Net Operating Leases 2021 $ 889,586 $ (403,345) $ 486,241 2022 5,868 — 5,868 2023 3,423 — 3,423 Total future minimum lease payments 898,877 $ (403,345) $ 495,532 Less imputed interest (29,380) Total $ 869,497

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2020
Stockholders' Equity Note [Abstract]
Summary of Warrant Activity and Changes in Warrants Outstanding	A summary of warrant activity and changes in warrants outstanding, including both liability and equity classifications, is presented below: Number of Weighted-Average Weighted-Average Remaining Contractual Term Balance outstanding, December 31, 2018 3,649,341 $ 8.91 4.4 years Granted 7,437,454 $ 1.87 Exercised (497,313) $ 6.60 Balance outstanding, December 31, 2019 10,589,482 $ 4.08 3.7 years Granted 5,831,451 $ 1.70 Exercised (11,159,941) $ 2.31 Balance outstanding, December 31, 2020 5,260,992 $ 5.19 4.1 years The above table excludes pre-funded warrants with a nominal exercise price of $.01 per share: 1. 605,072 pre-funded warrants outstanding as of December 31, 2019; 2. 386,967 pre-funded warrants which were issued during the twelve months ending December 31, 2020; 3. All 992,039 pre-funded warrants were exercised in full during the twelve months ending December 31, 2020.
Schedule of Preferred Stock	A summary of our Company's classes of preferred stock is presented below: Shares outstanding Class Par value Shares designated Liquidation preference As of December 31, 2020 As of December 31, 2019 Series A Convertible Preferred Stock $ 0.001 277,100 $ 606,000 60,600 60,600 Series B Convertible Preferred Stock $ 0.001 8,860 None — — Series C Convertible Preferred Stock $ 0.001 200,000 None — — Series D Convertible Preferred Stock $ 0.0001 154,670 None — — Series E Convertible Preferred Stock $ 0.001 865,824 None 655,044 —

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2020
Share-based Payment Arrangement [Abstract]
Stock-based compensation recognized	Stock-based compensation has been recognized in operating results as follows: Years ended December 31, 2020 2019 Research and development expenses 354,692 399,687 Selling, general and administrative expenses 1,410,112 485,256 Total stock-based compensation $ 1,764,804 $ 884,943
Estimated Fair Value of Stock Options - Assumptions	The estimated fair value of stock option awards was determined on the date of grant using the Black-Scholes option valuation model with the following assumptions during the years indicated below: Years ended December 31, 2020 2019 Risk-free interest rate 0.39% - 0.93% 1.66% - 2.33% Dividend yield 0% 0% Expected volatility (range) 102% - 106% 95% - 99% Expected volatility (weighted-average) 105% 96% Expected term (in years) 5.9 years 5.9 years
Summary of Stock Option Activity	A summary of stock option activity and of changes in stock options outstanding is presented below: Number of Options Weighted-Average Exercise Price Per Share Intrinsic Weighted-Average Balance outstanding, December 31, 2019 1,015,418 $ 12.77 $ — 9.1 years Granted 969,965 $ 2.53 Exercised (60,195) $ 2.46 $ 970,145 Forfeited (48,537) $ 22.91 Expired (16,144) $ 21.29 Balance outstanding, December 31, 2020 1,860,507 $ 7.43 $ 27,963,363 8.9 years Vested and exercisable, December 31, 2020 753,206 $ 14.63 $ 10,837,211 8.5 years Vested and expected to vest, December 31, 2020 1,777,407 $ 7.65 $ 26,682,849 8.9 years
Summary of Restricted Stock Unit Activity	A summary of the RSU's activity is presented below: Number of Shares Weighted Average Intrinsic Non-vested RSU's outstanding, December 31, 2018 30,132 $ 14.36 $ 95,005 Granted 9,167 $ 1.61 Vested (22,057) $ 8.68 Forfeited (5,941) $ 13.82 Non-vested RSU's outstanding, December 31, 2019 11,301 $ 15.38 $ 14,013 Vested (10,810) $ 9.37 Non-vested RSU's outstanding, December 31, 2020 491 $ 147.60 $ 7,641

Derivative Financial Instrume_2

Derivative Financial Instruments - Warrants (Tables) - Black Scholes Option Pricing Method	12 Months Ended
	Dec. 31, 2020
Derivative financial instruments
Schedule of Assumptions Used to Determine the Fair Value of Warrants	The range of assumptions used to determine the fair value of the warrants valued using the Black-Scholes option pricing model during the periods indicated was: Year ended December 31, 2020 2019 Fair value of Cardiff Oncology common stock $1.01 - $17.99 $1.24 - $3.75 Expected warrant term 2.1 - 3.1 years 3.1 - 4.1 years Risk-free interest rate 0.13% - 1.62% 1.56% - 2.49% Expected volatility 110% - 118% 102% - 111% Dividend yield —% —% As of December 31, 2020 Weighted Average (1)(2) : Fair value of Cardiff Oncology common stock $17.99 Expected warrant term 2.1 years Risk-free interest rate 0.13 % Expected volatility of Cardiff Oncology common stock 116 % Dividend yield 0 % (1) Weighted average is only disclosed for periods after January 1, 2020 under the adoption of ASU 2018-13.
Schedule of Components of Changes in the Company’s Derivative Financial Instruments Liability Balance	The following table sets forth the components of changes in the Company’s derivative financial instruments — warrants liability balance, valued using the Black-Scholes option pricing method, for the periods indicated. Date Description Number of Warrants Derivative December 31, 2018 Balance of derivative financial instruments — warrants liability 64,496 $ 32,315 Change in fair value of derivative financial instruments — warrants during the year recognized as a gain in the statement of operations — (28,188) December 31, 2019 Balance of derivative financial instruments — warrants liability 64,496 4,127 Change in fair value of derivative financial instruments — warrants during the year recognized as a loss in the statement of operations — 280,844 December 31, 2020 Balance of derivative financial instruments — warrants liability 64,496 $ 284,971

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2020
Fair Value Disclosures [Abstract]
Schedule of Company’s Assets and Liabilities that are Measured and Recognized at Fair Value on a Recurring Basis Classified Under the Appropriate Level of the Fair Value Hierarchy	The following table presents the Company’s assets and liabilities that are measured and recognized at fair value on a recurring basis classified under the appropriate level of the fair value hierarchy as of December 31, 2020 and 2019: Fair Value Measurements at Quoted Prices in Active Markets for Identical Assets and Liabilities Significant Other Observable Inputs Significant Unobservable Inputs Total Assets: Money market fund (1) $ 129,987,804 $ — $ — $ 129,987,804 Total Assets $ 129,987,804 $ — $ — $ 129,987,804 Liabilities: Derivative financial instruments — warrants $ — $ — $ 284,971 $ 284,971 Total Liabilities $ — $ — $ 284,971 $ 284,971 Fair Value Measurements at Quoted Prices in Active Markets for Identical Assets and Liabilities Significant Other Observable Inputs Significant Unobservable Inputs Total Assets: Money market fund (1) $ 10,131,240 $ — $ — $ 10,131,240 Total Assets $ 10,131,240 $ — $ — $ 10,131,240 Liabilities: Derivative financial instruments — warrants $ — $ — $ 4,127 $ 4,127 Total Liabilities $ — $ — $ 4,127 $ 4,127 (1) Included as a component of cash and cash equivalents on the accompanying balance sheet.

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Provision for Income Taxes Based on Losses from Continuing Operations	The provision for income taxes based on losses from continuing operations consists of the following at December 31 (in thousands): Years ended December 31, 2020 2019 Current: State $ 1 $ 1 Total current provision 1 1 Deferred: Federal (4,043) (2,634) State (92) (148) Total deferred (benefit) expense (4,135) (2,782) Valuation allowance 4,134 2,781 Total income tax provision $ — $ —
Schedule of Significant Components of the Company’s Taxes and the Rates	Significant components of the Company’s taxes and the rates as of December 31 are shown below (in thousands, except percentages): Years ended December 31, 2020 2019 Tax computed at the federal statutory rate $ (4,054) 21 % $ (3,447) 21 % State tax, net of federal tax benefit (122) 1 % (177) 1 % Permanent Items 261 (1) % 353 (2) % Stock options true-up 81 (1) % 875 (5) % Tax credits (300) 2 % (384) 2 % Valuation allowance increase (decrease) 4,134 (22) % 2,780 (17) % Provision for income taxes $ — — % $ — — %
Schedule of Significant Components of the Company’s Deferred Tax Assets	Significant components of the Company’s deferred tax assets and liabilities from federal and state income taxes as of December 31 are shown below (in thousands): Years ended December 31, 2020 2019 Deferred tax assets: Tax loss carryforwards $ 42,331 $ 38,494 Research and development credits and other tax credits 3,904 3,710 Stock-based compensation 684 531 Other 1,116 1,252 Total deferred tax assets 48,035 43,987 Deferred tax liabilities: Operating lease right-of-use assets (74) (154) Other (6) (12) Total deferred tax liabilities (80) (166) Net deferred tax assets before valuation allowance 47,955 43,821 Valuation allowance (47,955) (43,821) Net deferred tax asset $ — $ —

Business Overview and Liquidi_2

Business Overview and Liquidity (Details) - USD ($)	Dec. 31, 2020	Dec. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Cash and cash equivalents	$ 130,980,681	$ 10,195,292

Basis of Presentation and Sum_4

Basis of Presentation and Summary of Significant Accounting Policies - Narrative (Details)	12 Months Ended
	Dec. 31, 2020USD ($)segment
Accounting Policies [Abstract]
Number of operating segments | segment	1
Accrued Clinical Trial Expenses	$ 1,683,195
Research and development expense	$ 11,235,396
Payment terms	Payment terms and conditions vary by contracts, although terms generally include a requirement of payment within 30 to 45 days after invoice.

Basis of Presentation and Sum_5

Basis of Presentation and Summary of Significant Accounting Policies - Warrants (Details) - USD ($)	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Derivative financial instruments
Derivative financial instruments—warrants	$ 284,971	$ 4,127
Warrants to purchase Common Stock | Black Scholes Option Pricing Method
Derivative financial instruments
Derivative financial instruments—warrants	$ 284,971	$ 4,127	$ 32,315

Basis of Presentation and Sum_6

Basis of Presentation and Summary of Significant Accounting Policies - Long-Lived Assets (Details)	12 Months Ended
	Dec. 31, 2020
Laboratory equipment
Property, Plant and Equipment [Line Items]
Estimated useful lives	5 years
Furniture and office equipment | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful lives	3 years
Furniture and office equipment | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful lives	5 years

Basis of Presentation and Sum_7

Basis of Presentation and Summary of Significant Accounting Policies - Anti-dilutive Share Equivalents (Details) - shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Net Loss Per Share
Antidilutive securities excluded from computation of earnings per share (in shares)	9,807,474	11,617,078
Options to purchase Common Stock
Net Loss Per Share
Antidilutive securities excluded from computation of earnings per share (in shares)	1,860,507	1,015,418
Warrants to purchase Common Stock
Net Loss Per Share
Antidilutive securities excluded from computation of earnings per share (in shares)	5,260,992	10,589,482
Restricted Stock Units
Net Loss Per Share
Antidilutive securities excluded from computation of earnings per share (in shares)	491	11,301
Series A Convertible Preferred Stock
Net Loss Per Share
Antidilutive securities excluded from computation of earnings per share (in shares)	877	877
Series E Convertible Preferred Stock
Net Loss Per Share
Antidilutive securities excluded from computation of earnings per share (in shares)	2,684,607	0

Supplementary Balance Sheet I_3

Supplementary Balance Sheet Information - Property and Equipment (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Depreciation and amortization	$ 466,009	$ 494,232
Property and equipment	3,627,719	3,482,116
Less—accumulated depreciation	(3,004,025)	(2,604,293)
Property and equipment, net	623,694	877,823
Furniture and office equipment
Property, Plant and Equipment [Line Items]
Property and equipment	797,739	775,030
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment	1,962,230	1,962,230
Laboratory equipment
Property, Plant and Equipment [Line Items]
Property and equipment	$ 867,750	$ 744,856

Supplementary Balance Sheet I_4

Supplementary Balance Sheet Information - Accrued Expenses (Details) - USD ($)	Dec. 31, 2020	Dec. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Accrued compensation	$ 1,523,321	$ 1,003,383
Preferred stock dividend	389,495	365,255
Clinical trials	1,557,134	1,504,660
Clinical trials	66,593	181,408
Director fees	92,500	67,500
Professional fees and outside services	38,180	21,000
Patent, license and other fees	117,440	69,950
Other accrued liabilities	66,100	46,905
Total accrued liabilities	$ 3,850,763	$ 3,260,061

Leases - Narrative (Details)

Leases - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Leases [Abstract]
Monthly rent payments	$ 78,000
Annual rent increase, percentage	3.00%
Number of subleases	3
Impairment loss	$ 34,169	$ 0

Leases - Lease Expense (Details

Leases - Lease Expense (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Leases [Abstract]
Operating lease cost	$ 441,529	$ 444,878
Operating sublease income	(291,173)	(381,653)
Net operating lease cost	$ 150,356	$ 63,225

Leases - Supplemental Balance S

Leases - Supplemental Balance Sheet Information (Details) - USD ($)	Dec. 31, 2020	Dec. 31, 2019
Leases [Abstract]
Operating lease right-of-use assets	$ 343,001	$ 697,418
Current operating lease liabilities	860,206	865,379
Non-current operating lease liabilities	9,291	860,963
Total operating lease liabilities	$ 869,497	$ 1,726,342
Weighted-average remaining lease term–operating leases	1 year	2 years
Weighted-average discount rate–operating leases	6.50%	6.50%

Leases - Supplemental Cash Flow

Leases - Supplemental Cash Flow Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Leases [Abstract]
Operating cash flows from operating leases	$ 943,959	$ 916,762

Leases - Future Minimum Lease P

Leases - Future Minimum Lease Payments (Details) - USD ($)	Dec. 31, 2020	Dec. 31, 2019
Operating Leases
2021	$ 889,586
2022	5,868
2023	3,423
Total future minimum lease payments	898,877
Less imputed interest	(29,380)
Total	869,497	$ 1,726,342
Sublease Income
2021	(403,345)
2022	0
2023	0
Total future minimum lease payments	(403,345)
Net Operating Leases
2021	486,241
2022	5,868
2023	3,423
Total future minimum lease payments	$ 495,532

Stockholders' Equity - Schedule

Stockholders' Equity - Schedule of Warrants (Details) - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Jun. 15, 2020
Number of Warrants
Balance of warrants outstanding at the beginning of the period (in shares)	10,589,482	3,649,341
Granted (in shares)	5,831,451	7,437,454
Exercised (in shares)	(11,159,941)	(497,313)
Balance of warrants outstanding at the end of the period (in shares)	5,260,992	10,589,482	3,649,341
Weighted-Average Exercise Price Per Share
Weighted average exercise price of warrants at the beginning of the period (in dollars per share)	$ 4.08	$ 8.91
Granted (in dollars per share)	1.70	1.87
Exercised (in dollars per share)	2.31	6.60
Weighted average exercise price of warrants at the end of the period (in dollars per share)	$ 5.19	$ 4.08	$ 8.91
Weighted-Average Remaining Contractual Term
Weighted-Average Remaining Contractual Term	4 years 1 month 6 days	3 years 8 months 12 days	4 years 4 months 24 days
Exercise price of warrants (in dollars per share)	$ 0.01			$ 3.05
Pre-Funded Warrants
Number of Warrants
Balance of warrants outstanding at the beginning of the period (in shares)	605,072
Granted (in shares)	386,967
Exercised (in shares)	(992,039)
Balance of warrants outstanding at the end of the period (in shares)		605,072

Stockholders' Equity - Summary

Stockholders' Equity - Summary of Preferred Stock (Details) - USD ($)	Dec. 31, 2020	Jun. 15, 2020	Dec. 31, 2019
Class of Stock [Line Items]
Preferred stock, par value (in dollars per share)	$ 0.001		$ 0.001
Preferred stock, shares authorized (in shares)	20,000,000		20,000,000
Series A Convertible Preferred Stock
Class of Stock [Line Items]
Preferred stock, par value (in dollars per share)	$ 0.001
Preferred stock, shares authorized (in shares)	277,100
Series A Convertible Preferred Stock, liquidation preference	$ 606,000
Preferred stock, shares outstanding (in shares)	60,600		60,600
Series B Convertible Preferred Stock
Class of Stock [Line Items]
Preferred stock, par value (in dollars per share)	$ 0.001
Preferred stock, shares authorized (in shares)	8,860
Preferred stock, shares outstanding (in shares)	0		0
Series C Convertible Preferred Stock
Class of Stock [Line Items]
Preferred stock, par value (in dollars per share)	$ 0.001
Preferred stock, shares authorized (in shares)	200,000
Preferred stock, shares outstanding (in shares)	0		0
Series D Convertible Preferred Stock
Class of Stock [Line Items]
Preferred stock, par value (in dollars per share)	$ 0.0001
Preferred stock, shares authorized (in shares)	154,670
Preferred stock, shares outstanding (in shares)	0		0
Series E Convertible Preferred Stock
Class of Stock [Line Items]
Preferred stock, par value (in dollars per share)	$ 0.001	$ 10
Preferred stock, shares authorized (in shares)	865,824
Preferred stock, shares outstanding (in shares)	655,044		0

Stockholders' Equity - Series A

Stockholders' Equity - Series A Convertible Preferred Stock (Details) - USD ($)	Mar. 17, 2006	Sep. 30, 2005	Dec. 31, 2020	Dec. 31, 2019
Class of Stock [Line Items]
Accrued dividend during the period			$ 24,240	$ 24,240
Accumulated Deficit
Class of Stock [Line Items]
Accrued dividend during the period			$ 24,240	24,240
Series A Convertible Preferred Stock
Class of Stock [Line Items]
Cumulative dividend rate (as a percent)			4.00%
Accrued cumulative unpaid preferred stock dividends			$ 389,495	$ 365,255
Stated value (in dollars per share)			$ 10
Conversion price per share (in dollars per share)	$ 691.20	$ 928.80	691.20
Period during which the conversion price is subject to adjustment for dilutive issuances	12 months
Share price for 20 consecutive trading days for automatic conversion			$ 1,857.60
Number of consecutive trading days in which the closing price of the entity's common stock must equal or exceed a specified price in order for the preferred stock to be automatically converted			20 days
Number of common stock shares traded per day during the 20 trading days for the preferred stock to be automatically converted			116
Number of trading days in which the specified volume of common stock must be traded for the preferred stock to be automatically converted			20 days

Stockholders' Equity - Series C

Stockholders' Equity - Series C Convertible Preferred Stock (Details) - USD ($)	Jun. 15, 2020	May 08, 2020	Jan. 25, 2019	Jun. 30, 2020	Apr. 30, 2019	Dec. 31, 2020	Dec. 31, 2019
Class of Stock [Line Items]
Warrants granted (in shares)						5,831,451	7,437,454
Exercise price of warrants (in dollars per share)	$ 3.05					$ 0.01
Shares issued upon conversion (in shares)						863,852
Conversion of stock, shares issued (in shares)				1,546,700	333,333
Service receivable			$ 1,675,000			$ 2,171,258	$ 971,673
Deemed dividend recognized on beneficial conversion features of convertible preferred stock	$ 2,700,000
Series C Convertible Preferred Stock
Class of Stock [Line Items]
Shares converted (in shares)					200,000
Series C Convertible Preferred Stock
Class of Stock [Line Items]
Deemed dividend recognized on beneficial conversion features of convertible preferred stock			300,000			$ 0	$ 268,269
Private Placement
Class of Stock [Line Items]
Amount financed under agreement		$ 2,300,000	$ 1,675,000
Warrants granted (in shares)			150,000
Exercise price of warrants (in dollars per share)		$ 1.50	$ 3.762
Private Placement | Common Stock
Class of Stock [Line Items]
Stock issued (in shares)		602,833	183,334
Shares issued upon conversion (in shares)			1.67
Private Placement | Series C Convertible Preferred Stock
Class of Stock [Line Items]
Stock issued (in shares)			200,000

Stockholders' Equity - Series D

Stockholders' Equity - Series D Convertible Preferred Stock (Details) - USD ($)	Jun. 15, 2020	May 08, 2020	Jan. 25, 2019	Jun. 30, 2020	Apr. 30, 2019	Dec. 31, 2020	Dec. 31, 2019
Class of Stock [Line Items]
Number of shares called by warrants (in shares)	2,213,115
Exercise price of warrants (in dollars per share)	$ 3.05					$ 0.01
Conversion of stock, shares issued (in shares)				1,546,700	333,333
Service receivable			$ 1,675,000			$ 2,171,258	$ 971,673
Deemed dividend recognized on beneficial conversion features of convertible preferred stock	$ 2,700,000
Months until exercisable	6 months	6 months
Series D Convertible Preferred Stock
Class of Stock [Line Items]
Shares converted (in shares)				154,670
Service receivable		$ 2,300,000
Deemed dividend recognized on beneficial conversion features of convertible preferred stock		600,000
Private Placement
Class of Stock [Line Items]
Amount financed under agreement		$ 2,300,000	$ 1,675,000
Number of shares called by warrants (in shares)		859,813
Exercise price of warrants (in dollars per share)		$ 1.50	$ 3.762
Private Placement | Common Stock
Class of Stock [Line Items]
Stock issued (in shares)		602,833	183,334
Private Placement | Series D Convertible Preferred Stock
Class of Stock [Line Items]
Stock issued (in shares)		154,670

Stockholders' Equity - Series E

Stockholders' Equity - Series E Convertible Preferred Stock (Details) - USD ($)

Oct. 02, 2020

Jun. 15, 2020

May 26, 2020

May 14, 2020

May 11, 2020

May 08, 2020

Apr. 09, 2020

Mar. 30, 2020

Dec. 31, 2020

Dec. 31, 2020

Dec. 31, 2019

Jan. 25, 2019

Class of Stock [Line Items]

Sale of stock, shares issued (in shares)

6,500,000

1,205,400

146,854

447,761

904,970

800,000

Number of shares called by warrants (in shares)

2,213,115

Months until exercisable

6 months

6 months

Exercise price of warrants (in dollars per share)

$ 3.05

$ 0.01

$ 0.01

Shares issued upon conversion (in shares)

863,852

863,852

Class Of Warrant Or Right, Issued

184,426

Deemed dividend recognized on beneficial conversion features of convertible preferred stock

$ 2,700,000

Expiration term

5 years 6 months

Warrants, Fair Value

$ 370,666

$ 370,666

Series N Warrant

Class of Stock [Line Items]

Months until exercisable

6 months

Exercise price of warrants (in dollars per share)

$ 2.39

Series E Convertible Preferred Stock

Class of Stock [Line Items]

Conversion price (in dollars per share)

$ 2.44

Shares converted (in shares)

210,780

Deemed dividend recognized on beneficial conversion features of convertible preferred stock

$ 2,664,717

$ 0

Registered Direct Offering

Class of Stock [Line Items]

Sale of stock, shares issued (in shares)

1,984,328

Private Placement

Class of Stock [Line Items]

Number of shares called by warrants (in shares)

859,813

Exercise price of warrants (in dollars per share)

$ 1.50

$ 3.762

Private Placement | Series E Convertible Preferred Stock

Class of Stock [Line Items]

Sale of stock, shares issued (in shares)

865,824

Stockholders' Equity - Securiti

Stockholders' Equity - Securities Purchase Agreements (Details) - USD ($)	Oct. 02, 2020	Jun. 15, 2020	May 26, 2020	May 14, 2020	May 14, 2020	May 11, 2020	May 08, 2020	Apr. 09, 2020	Mar. 30, 2020	Dec. 31, 2020
Class of Stock [Line Items]
Sale of stock, shares issued (in shares)	6,500,000		1,205,400	146,854		447,761		904,970	800,000
Number of shares called by warrants (in shares)		2,213,115
Months until exercisable		6 months					6 months
Exercise price of warrants (in dollars per share)		$ 3.05								$ 0.01
Expiration term		5 years 6 months
Gross proceeds	$ 100,900,000		$ 2,500,000		$ 810,000			$ 1,100,000	$ 1,000,000
Offering price (in dollars per share)	$ 13.50			$ 1.43	$ 1.43	$ 1.34
Net proceeds	$ 94,000,000									$ 112,299,949	[1]
Over-Allotment Option
Class of Stock [Line Items]
Sale of stock, shares issued (in shares)	975,000
Series I Warrant
Class of Stock [Line Items]
Number of shares called by warrants (in shares)									131,967
Series J Warrant
Class of Stock [Line Items]
Number of securities called by each warrant (in shares)									1
Months until exercisable									6 months
Exercise price of warrants (in dollars per share)									$ 0.948
Expiration term									5 years 6 months
Series K Warrant
Class of Stock [Line Items]
Number of shares called by warrants (in shares)								255,000
Series L Warrants
Class of Stock [Line Items]
Number of securities called by each warrant (in shares)								1
Months until exercisable								6 months
Exercise price of warrants (in dollars per share)								$ 0.81
Expiration term								5 years 6 months
Series M Warrant
Class of Stock [Line Items]
Number of shares called by warrants (in shares)			482,160
Months until exercisable			6 months
Exercise price of warrants (in dollars per share)			$ 2.024
Expiration term			5 years 6 months
[1]	Net of expenses of $7,507,123, and fair value of warrants issued as a transaction advisory fee as of the date of issuance of $370,666

Stock-Based Compensation - Narr

Stock-Based Compensation - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Apr. 06, 2020	Jun. 06, 2019	Dec. 31, 2018	Sep. 17, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of shares vested	$ 1,522,984	$ 386,654
Intrinsic value, exercised		$ 0
Options to purchase Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average grant date fair value (in dollars per share)	$ 2.09	$ 1.91
Unrecognized compensation cost for non-vested options	$ 1,519,004
Period for recognition	1 year 10 months 24 days
Intrinsic value, exercised	$ 970,145
Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of vested awards	$ 101,290	$ 191,436
Equity Incentive Plan 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized (in shares)			2,243,056	1,243,056	243,056	34,722
Shares available for issuance (in shares)	260,446

Stock-Based Compensation - Stoc

Stock-Based Compensation - Stock-Based Compensation (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation	$ 1,764,804	$ 884,943
Research and development expenses
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation	354,692	399,687
Selling, general and administrative expenses
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation	$ 1,410,112	$ 485,256

Stock-Based Compensation - Assu

Stock-Based Compensation - Assumptions Using Black-Scholes for Estimated Fair Value of Stock Options (Details) - Options to purchase Common Stock	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Dividend yield	0.00%	0.00%
Expected volatility (weighted-average)	105.00%	96.00%
Expected term (in years)	5 years 10 months 24 days	5 years 10 months 24 days
Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Risk-free interest rate	0.39%	1.66%
Expected volatility (range)	102.00%	95.00%
Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Risk-free interest rate	0.93%	2.33%
Expected volatility (range)	106.00%	99.00%

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Stock Options Activity (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Weighted-Average Exercise Price Per Share
Intrinsic value, exercised		$ 0
Options to purchase Common Stock
Number of Options
Beginning balance (in shares)	1,015,418
Granted (in shares)	969,965
Exercised (in shares)	(60,195)
Forfeitures (in shares)	(48,537)
Expired (in shares)	(16,144)
Ending balance (in shares)	1,860,507	1,015,418
Vested and exercisable (in shares)	753,206
Vested and expected to vest (in shares)	1,777,407
Weighted-Average Exercise Price Per Share
Outstanding (in dollars per share)	$ 12.77
Granted (in dollars per share)	2.53
Exercised (in dollars per share)	2.46
Forfeited (in dollars per share)	22.91
Expired (in dollars per share)	21.29
Outstanding (in dollars per share)	7.43	$ 12.77
Vested and exercisable (in dollars per share)	14.63
Vested and expected to vest (in dollars per share)	$ 7.65
Intrinsic value, outstanding	$ 27,963,363	$ 0
Intrinsic value, exercised	970,145
Intrinsic value, vested and exercisable	10,837,211
Intrinsic value, vested and expected to vest	$ 26,682,849
Weighted average remaining contract term, outstanding	8 years 10 months 24 days	9 years 1 month 6 days
Weighted average remaining contractual term, exercisable	8 years 6 months
Weighted average remaining contractual term, vested and expected to vest	8 years 10 months 24 days

Stock-Based Compensation - Rest

Stock-Based Compensation - Restricted Stock Units (Details) - Restricted Stock Units - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Number of Shares
Beginning balance (in shares)	11,301	30,132
Granted (in shares)		9,167
Released (in shares)	(10,810)	(22,057)
Forfeited (in shares)		(5,941)
Ending balance (in shares)	491	11,301
Weighted Average Grant Date Fair Value Per Share
Beginning weighted average grant date fair value (in dollars per share)	$ 147.60	$ 15.38
Granted (in dollars per share)		1.61
Released (in dollars per share)	9.37	8.68
Forfeitures (in dollars per share)		13.82
Ending weighted average grant date fair value (in dollars per share)	$ 15.38	$ 14.36
Intrinsic value, outstanding	$ 7,641	$ 14,013	$ 95,005

Derivative Financial Instrume_3

Derivative Financial Instruments - Warrants (Details)	12 Months Ended
	Dec. 31, 2020USD ($)$ / sharesshares	Dec. 31, 2019USD ($)$ / sharesshares
Changes in the Company's derivative financial instruments liability balance
Balance of warrants outstanding at the beginning of the period (in shares) | shares	10,589,482	3,649,341
Balance of warrants outstanding at the end of the period (in shares) | shares	5,260,992	10,589,482
Balance of derivative financial instruments liability at the beginning of the period	$ 4,127
Change in fair value of derivative financial instruments—warrants during the year recognized as a loss in the statement of operations	280,844	$ (28,188)
Balance of derivative financial instruments liability at the end of the period	$ 284,971	$ 4,127
Warrants to purchase Common Stock
Changes in the Company's derivative financial instruments liability balance
Weighted average remaining contractual life	2 years 1 month 6 days	3 years 1 month 6 days
Warrants to purchase Common Stock | Weighted Average
Range of assumptions used to determine the fair value of warrants
Estimated fair value of Trovagene common stock (in dollars per share) | $ / shares	$ 17.99
Warrants to purchase Common Stock | Black Scholes Option Pricing Method
Changes in the Company's derivative financial instruments liability balance
Balance of warrants outstanding at the beginning of the period (in shares) | shares	64,496	64,496
Balance of warrants outstanding at the end of the period (in shares) | shares	64,496	64,496
Balance of derivative financial instruments liability at the beginning of the period	$ 4,127	$ 32,315
Change in fair value of derivative financial instruments—warrants during the year recognized as a loss in the statement of operations	280,844	(28,188)
Balance of derivative financial instruments liability at the end of the period	$ 284,971	$ 4,127
Warrants to purchase Common Stock | Black Scholes Option Pricing Method | Minimum
Range of assumptions used to determine the fair value of warrants
Estimated fair value of Trovagene common stock (in dollars per share) | $ / shares	$ 1.01	$ 1.24
Warrants to purchase Common Stock | Black Scholes Option Pricing Method | Maximum
Range of assumptions used to determine the fair value of warrants
Estimated fair value of Trovagene common stock (in dollars per share) | $ / shares	$ 17.99	$ 3.75
Expected term | Warrants to purchase Common Stock | Weighted Average
Range of assumptions used to determine the fair value of warrants
Expected warrant term	2 years 1 month 6 days
Expected term | Warrants to purchase Common Stock | Black Scholes Option Pricing Method | Minimum
Range of assumptions used to determine the fair value of warrants
Expected warrant term	2 years 1 month 6 days	3 years 1 month 6 days
Expected term | Warrants to purchase Common Stock | Black Scholes Option Pricing Method | Maximum
Range of assumptions used to determine the fair value of warrants
Expected warrant term	3 years 1 month 6 days	4 years 1 month 6 days
Risk-free interest rate | Warrants to purchase Common Stock | Weighted Average
Range of assumptions used to determine the fair value of warrants
Measurement input	0.0013
Risk-free interest rate | Warrants to purchase Common Stock | Black Scholes Option Pricing Method | Minimum
Range of assumptions used to determine the fair value of warrants
Measurement input	0.0013	0.0156
Risk-free interest rate | Warrants to purchase Common Stock | Black Scholes Option Pricing Method | Maximum
Range of assumptions used to determine the fair value of warrants
Measurement input	0.0162	0.0249
Expected volatility | Warrants to purchase Common Stock | Weighted Average
Range of assumptions used to determine the fair value of warrants
Measurement input	1.16
Expected volatility | Warrants to purchase Common Stock | Black Scholes Option Pricing Method | Minimum
Range of assumptions used to determine the fair value of warrants
Measurement input	1.10	1.02
Expected volatility | Warrants to purchase Common Stock | Black Scholes Option Pricing Method | Maximum
Range of assumptions used to determine the fair value of warrants
Measurement input	1.18	1.11
Dividend yield | Warrants to purchase Common Stock
Range of assumptions used to determine the fair value of warrants
Measurement input	0	0
Dividend yield | Warrants to purchase Common Stock | Weighted Average
Range of assumptions used to determine the fair value of warrants
Measurement input	0

Fair Value Measurements (Detail

Fair Value Measurements (Details) - USD ($)	Dec. 31, 2020	Dec. 31, 2019
Liabilities:
Derivative financial instruments—warrants	$ 284,971	$ 4,127
Recurring basis | Estimate of Fair Value Measurement
Assets:
Money market fund	129,987,804	10,131,240
Total Assets	129,987,804	10,131,240
Liabilities:
Derivative financial instruments—warrants	284,971	4,127
Total Liabilities	284,971	4,127
Recurring basis | Quoted Prices in Active Markets for Identical Assets and Liabilities (Level 1) | Estimate of Fair Value Measurement
Assets:
Money market fund	129,987,804	10,131,240
Total Assets	129,987,804	10,131,240
Liabilities:
Derivative financial instruments—warrants	0	0
Total Liabilities	0	0
Recurring basis | Significant Other Observable Inputs (Level 2) | Estimate of Fair Value Measurement
Assets:
Money market fund	0	0
Total Assets	0	0
Liabilities:
Derivative financial instruments—warrants	0	0
Total Liabilities	0	0
Recurring basis | Significant Unobservable Inputs (Level 3) | Estimate of Fair Value Measurement
Assets:
Money market fund	0	0
Total Assets	0	0
Liabilities:
Derivative financial instruments—warrants	284,971	4,127
Total Liabilities	$ 284,971	$ 4,127

Income Taxes - Narrative (Detai

Income Taxes - Narrative (Details)	12 Months Ended
	Dec. 31, 2020USD ($)
Operating loss carryforwards (NOLs)
Interest and/or penalties incurred	$ 0
Federal
Operating loss carryforwards (NOLs)
NOLs, subject to expiration	128,900,000
NOLs, not subject to expiration	48,400,000
California Franchise Tax Board
Operating loss carryforwards (NOLs)
NOLs	70,700,000
Capital Loss Carryforward
Operating loss carryforwards (NOLs)
Tax credits	700,000
R&D credits | Federal
Operating loss carryforwards (NOLs)
Tax credits	2,500,000
R&D credits | California Franchise Tax Board
Operating loss carryforwards (NOLs)
Tax credits	$ 1,800,000

Income Taxes - Provision for In

Income Taxes - Provision for Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Current:
State	$ 1	$ 1
Total current provision	1	1
Deferred:
Federal	(4,043)	(2,634)
State	(92)	(148)
Total deferred (benefit) expense	(4,135)	(2,782)
Valuation allowance	4,134	2,781
Total income tax provision	$ 0	$ 0

Income Taxes - Significant Comp

Income Taxes - Significant Components of Company's Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Effective Income Tax Rate Reconciliation, Amount [Abstract]
Tax computed at the federal statutory rate	$ (4,054)	$ (3,447)
State tax, net of federal tax benefit	(122)	(177)
Permanent Items	261	353
Stock options true-up	81	875
Tax credits	(300)	(384)
Valuation allowance increase (decrease)	4,134	2,780
Provision for income taxes	$ 0	$ 0
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Tax computed at the federal statutory rate	21.00%	21.00%
State tax, net of federal tax benefit	1.00%	1.00%
Permanent Items	(1.00%)	(2.00%)
Stock options true-up	(1.00%)	(5.00%)
Tax credits	2.00%	2.00%
Valuation allowance increase (decrease)	(22.00%)	(17.00%)
Provision for income taxes	0.00%	0.00%

Income Taxes - Significant Co_2

Income Taxes - Significant Components of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Deferred tax assets:
Tax loss carryforwards	$ 42,331	$ 38,494
Research and development credits and other tax credits	3,904	3,710
Stock-based compensation	684	531
Other	1,116	1,252
Total deferred tax assets	48,035	43,987
Deferred tax liabilities:
Operating lease right-of-use assets	(74)	(154)
Other	(6)	(12)
Total deferred tax liabilities	80	166
Net deferred tax assets before valuation allowance	47,955	43,821
Valuation allowance	(47,955)	(43,821)
Net deferred tax asset	$ 0	$ 0

Commitments and Contingencies -

Commitments and Contingencies - Research and Development and Clinical Trial Agreements (Details) - USD ($)	1 Months Ended	12 Months Ended
	Mar. 31, 2017	Dec. 31, 2020
Loss Contingencies [Line Items]
Research and development expense		$ 11,235,396
Norviano
Loss Contingencies [Line Items]
Licensing and distribution rights commitment		$ 1,000,000
Licensing Agreements | Norviano
Loss Contingencies [Line Items]
Research and development expense	$ 2,000,000

Related Party Transactions (Det

Related Party Transactions (Details) - USD ($)	Oct. 02, 2020	May 26, 2020	May 14, 2020	May 11, 2020	Apr. 09, 2020	Mar. 30, 2020	May 31, 2020	Dec. 31, 2020		Dec. 31, 2019
Related Party Transaction [Line Items]
Research and development expense								$ 11,235,396
Sale of stock, shares issued (in shares)	6,500,000	1,205,400	146,854	447,761	904,970	800,000
Offering price (in dollars per share)	$ 13.50		$ 1.43	$ 1.34
Net proceeds	$ 94,000,000							112,299,949	[1]
Other Affiliates
Related Party Transaction [Line Items]
Research and development expense								$ 1,083,000		$ 1,005,000
Director
Related Party Transaction [Line Items]
Sale of stock, shares issued (in shares)							447,761
Offering price (in dollars per share)							$ 1.34
Net proceeds							$ 600,000
[1]	Net of expenses of $7,507,123, and fair value of warrants issued as a transaction advisory fee as of the date of issuance of $370,666

COVID-19 (Details)

COVID-19 (Details) - Paycheck Protection Program, CARES Act	Apr. 15, 2020USD ($)
Unusual or Infrequent Item, or Both [Line Items]
Notes payable	$ 305,000
Interest rate	0.98%