Clearside Biomedical (CLSD) 10-Q 8 Nov 19 2019 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2019	Nov. 04, 2019
Cover [Abstract]
Entity Registrant Name	Clearside Biomedical, Inc.
Amendment Flag	false
Document Period End Date	Sep. 30, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q3
Trading Symbol	CLSD
Document Type	10-Q
Entity Central Index Key	0001539029
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	true
Entity Interactive Data Current	Yes
Document Transition Report	false
Title of 12(b) Security	Common Stock, par value $0.001 per share
Security Exchange Name	NASDAQ
Entity Incorporation, State or Country Code	DE
Document Quarterly Report	true
Entity Common Stock, Shares Outstanding		41,149,781
Entity Shell Company	false
Entity Current Reporting Status	Yes
Entity File Number	001-37783
Entity Tax Identification Number	45-2437375
Entity Address, Address Line One	900 North Point Parkway
Entity Address, Address Line Two	Suite 200
Entity Address, City or Town	Alpharetta
Entity Address, State or Province	GA
Entity Address, Postal Zip Code	30005
City Area Code	678
Local Phone Number	270-3631

Balance Sheets

Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 22,551	$ 8,043
Short-term investments		32,835
Prepaid expenses	1,468	2,049
Other current assets	27	17
Total current assets	24,046	42,944
Property and equipment, net	655	790
Operating lease right-of-use asset	806
Restricted cash	360	360
Other assets		26
Total assets	25,867	44,120
Current liabilities:
Accounts payable	1,429	6,869
Accrued liabilities	2,698	2,923
Current portion of long-term debt	5,833	556
Current portion of operating lease liabilities	483
Current portion of deferred rent		128
Other current liabilities	375
Total current liabilities	10,818	10,476
Long-term debt	4,329	9,419
Operating lease liabilities	961
Deferred rent		605
Total liabilities	16,108	20,500
Commitments and contingencies
Stockholders’ equity:
Preferred stock, $0.001 par value; 10,000,000 shares authorized and no shares issued at September 30, 2019 and December 31, 2018
Common stock, $0.001 par value; 100,000,000 shares authorized at September 30, 2019 and December 31, 2018; 41,149,781 and 32,119,227 shares issued and outstanding at September 30, 2019 and December 31, 2018, respectively	41	32
Additional paid-in capital	244,279	230,475
Accumulated deficit	(234,561)	(206,887)
Total stockholders’ equity	9,759	23,620
Total liabilities and stockholders’ equity	$ 25,867	$ 44,120

Balance Sheets (Parenthetical)

Balance Sheets (Parenthetical) - $ / shares	Sep. 30, 2019	Dec. 31, 2018
Statement Of Financial Position [Abstract]
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares issued	0	0
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares, issued	41,149,781	32,119,227
Common stock, shares outstanding	41,149,781	32,119,227

Statements of Operations

Statements of Operations - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Income Statement [Abstract]
Collaboration revenue	$ 141		$ 231
Type of Revenue [Extensible List]	clsd:CollaborationMember	clsd:CollaborationMember	clsd:CollaborationMember	clsd:CollaborationMember
Operating expenses:
Research and development	$ 2,728	$ 20,083	$ 14,353	$ 50,805
General and administrative	3,781	3,873	13,169	10,508
Total operating expenses	6,509	23,956	27,522	61,313
Loss from operations	(6,368)	(23,956)	(27,291)	(61,313)
Other (expense) income, net	(168)	84	(383)	133
Net loss	$ (6,536)	$ (23,872)	$ (27,674)	$ (61,180)
Net loss per share of common stock — basic and diluted	$ (0.17)	$ (0.75)	$ (0.75)	$ (2.02)
Weighted average shares outstanding — basic and diluted	38,414,751	32,024,223	36,747,314	30,292,909

Statement of Stockholders' Equi

Statement of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In-Capital	Accumulated Deficit	Accumulated Other Comprehensive Loss
Beginning balance at Dec. 31, 2017	$ 21,415	$ 25	$ 145,618	$ (124,220)	$ (8)
Beginning balance, shares at Dec. 31, 2017		25,354,651
Cumulative effect of accounting change	159			151	8
Issuance of common shares from follow-on public offering	79,581	$ 7	79,574
Issuance of common stock for follow-on public offering, shares		6,538,462
Exercise of stock options	237		237
Exercise of stock options, shares		53,920
Share-based compensation expense	1,138		1,138
Net loss	(16,607)			(16,607)
Ending balance at Mar. 31, 2018	85,923	$ 32	226,567	(140,676)
Ending balance, shares at Mar. 31, 2018		31,947,033
Beginning balance at Dec. 31, 2017	21,415	$ 25	145,618	(124,220)	$ (8)
Beginning balance, shares at Dec. 31, 2017		25,354,651
Net loss	(61,180)
Ending balance at Sep. 30, 2018	44,076	$ 32	229,293	(185,249)
Ending balance, shares at Sep. 30, 2018		32,024,223
Beginning balance at Mar. 31, 2018	85,923	$ 32	226,567	(140,676)
Beginning balance, shares at Mar. 31, 2018		31,947,033
Issuance of common shares under employee stock purchase plan	45		45
Issuance of common shares under employee stock purchase plan, shares		7,386
Exercise of stock options	196		196
Exercise of stock options, shares		69,804
Share-based compensation expense	1,199		1,199
Net loss	(20,701)			(20,701)
Ending balance at Jun. 30, 2018	66,662	$ 32	228,007	(161,377)
Ending balance, shares at Jun. 30, 2018		32,024,223
Share-based compensation expense	1,286		1,286
Net loss	(23,872)			(23,872)
Ending balance at Sep. 30, 2018	44,076	$ 32	229,293	(185,249)
Ending balance, shares at Sep. 30, 2018		32,024,223
Beginning balance at Dec. 31, 2018	23,620	$ 32	230,475	(206,887)
Beginning balance, shares at Dec. 31, 2018		32,119,227
Issuance of common shares from at-the-market sales agreement	6,627	$ 5	6,622
Issuance of common shares from at-the-market sales agreement, shares		4,660,966
Exercise of stock options	1		1
Exercise of stock options, shares		2,727
Share-based compensation expense	1,247		1,247
Net loss	(15,404)			(15,404)
Ending balance at Mar. 31, 2019	16,091	$ 37	238,345	(222,291)
Ending balance, shares at Mar. 31, 2019		36,782,920
Beginning balance at Dec. 31, 2018	23,620	$ 32	230,475	(206,887)
Beginning balance, shares at Dec. 31, 2018		32,119,227
Net loss	(27,674)
Ending balance at Sep. 30, 2019	9,759	$ 41	244,279	(234,561)
Ending balance, shares at Sep. 30, 2019		41,149,781
Beginning balance at Mar. 31, 2019	16,091	$ 37	238,345	(222,291)
Beginning balance, shares at Mar. 31, 2019		36,782,920
Issuance of common shares from at-the-market sales agreement	1,273	$ 1	1,272
Issuance of common shares from at-the-market sales agreement, shares		945,974
Issuance of common shares under employee stock purchase plan	15		15
Issuance of common shares under employee stock purchase plan, shares		17,252
Share-based compensation expense	1,256		1,256
Net loss	(5,734)			(5,734)
Ending balance at Jun. 30, 2019	12,901	$ 38	240,888	(228,025)
Ending balance, shares at Jun. 30, 2019		37,746,146
Issuance of common shares from at-the-market sales agreement	2,419	$ 3	2,416
Issuance of common shares from at-the-market sales agreement, shares		3,370,000
Exercise of stock options	5		5
Exercise of stock options, shares		13,635
Vesting of restricted stock units, shares		20,000
Share-based compensation expense	970		970
Net loss	(6,536)			(6,536)
Ending balance at Sep. 30, 2019	$ 9,759	$ 41	$ 244,279	$ (234,561)
Ending balance, shares at Sep. 30, 2019		41,149,781

Statements of Cash Flows

Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Operating activities
Net loss	$ (27,674)	$ (61,180)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	160	141
Share-based compensation expense	3,473	3,623
Non-cash interest expense	141	107
Accretion of debt discount	46	95
Amortization and accretion on available-for-sale investments, net	(115)	(514)
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	571	(1,686)
Other assets and liabilities	306	(81)
Accounts payable and accrued liabilities	(5,665)	4,554
Net cash used in operating activities	(28,757)	(54,941)
Investing activities
Maturities of available-for-sale investments	32,950	59,970
Purchase of available-for-sale investments		(80,137)
Acquisition of property and equipment	(25)	(34)
Net cash provided by (used in) investing activities	32,925	(20,201)
Financing activities
Proceeds from at-the-market sales agreement, net of issuance costs	10,319
Proceeds from follow-on public offering, net of issuance costs		79,581
Proceeds from exercise of stock options	6	433
Proceeds from shares issued under employee stock purchase plan	15	45
Proceeds from long-term debt		10,000
Payments made on long-term debt		(8,300)
Net cash provided by financing activities	10,340	81,759
Net increase in cash, cash equivalents and restricted cash	14,508	6,617
Cash, cash equivalents and restricted cash, beginning of period	8,403	9,584
Cash, cash equivalents and restricted cash, end of period	22,911	16,201
Reconciliation of cash, cash equivalents and restricted cash
Cash and cash equivalents	22,551	15,841
Restricted cash	360	360
Cash, cash equivalents and restricted cash, end of period	$ 22,911	$ 16,201

The Company

The Company	9 Months Ended
	Sep. 30, 2019
Organization Consolidation And Presentation Of Financial Statements [Abstract]
The Company	1. The Company Clearside Biomedical, Inc. (the “Company”) is a clinical biopharmaceutical company developing first-in-class pharmacological therapies to restore and preserve vision for people with serious eye diseases. The Company’s current product candidates focus on treatments for diseases affecting the retina and choroid and are injected into the suprachoroidal space (“SCS”) using its proprietary SCS Microinjector™. Incorporated in the State of Delaware on May 26, 2011, the Company has its corporate headquarters in Alpharetta, Georgia. The Company’s activities since inception have primarily consisted of developing product and technology rights, raising capital and performing research and development activities. The Company has no current source of revenue to sustain present activities and does not expect to generate meaningful revenue until and unless the Company receives regulatory approval of and successfully commercializes its product candidates. The Company is subject to a number of risks and uncertainties similar to those of other life science companies at a similar stage of development, including, among others, the need to obtain adequate additional financing, successful development efforts, regulatory approval of products, compliance with government regulations, successful commercialization of potential products, protection of proprietary technology and dependence on key individuals. Liquidity The Company has funded its operations primarily through the sale of convertible preferred stock and common stock and the issuance of long-term debt. On June 30, 2017, the Company entered into an at-the-market sales agreement (“the ATM agreement”) with Cowen and Company LLC (“Cowen”) under which the Company may offer and sell, from time to time at its sole discretion, shares of its common stock having an aggregate offering price of up to $50.0 million through Cowen acting as sales agent. During the nine months ended September 30, 2019, the Company sold 9.0 million shares of its common stock for net proceeds of $10.3 million under the ATM agreement. The Company’s registration statement on Form S- 3 contemplated under the ATM agreement was declared effective by the SEC on July 13, 2017. The registration statement on Form S- 3 includes a prospectus supplement covering the offering up to $18.5 million of shares of common stock over the 12 months ending March 15, 2020 in accordance with the ATM agreement. On October 22, 2019, the Company entered into a License Agreement (the “License Agreement”) with Bausch Health Ireland Limited (“Bausch”). Under the License Agreement, the Company has granted an exclusive license to Bausch for the commercialization and development of XIPERE TM Subsequent Events In connection with the entry by the Company into the License Agreement, on October 18, 2019, the Company entered into a Third Amendment to Second Amended and Restated Loan and Security Agreement (the “3 rd rd Long-Term Debt ). The Company will need to obtain additional resources to fund future operations, including to conduct additional clinical trials and to complete the development of its product candidates. If any such products were to receive regulatory approval, the Company may need to prepare for the potential commercialization of its product candidates, which could include additional collaborations with third parties for the commercial launch of the products. The Company had cash and cash equivalents of $22.6 million as of September 30, 2019. The Company has suffered recurring losses and negative cash flows from operations since inception and anticipates incurring additional losses until such time, if ever, that it can obtain approval from the U.S. Food and Drug Administration (the “FDA”) to market and then generate significant revenue from any of its product candidates. The Company will need additional resources to fund its operations and Based on its current license agreements, research and development plans and forecasted expenses, the Company expects that its existing cash and cash equivalents as of the filing date, November 8, 2019, will enable it to fund its operating expenses and capital expenditure requirements into the third quarter of 2020. The Company’s ability to fund its operations into the third quarter of 2020 gives effect to the potential restriction of cash pursuant to the Second Amended and Restated Loan and Security Agreement, as amended by the 3 rd The Company’s financial statements have been prepared on a going concern basis, which contemplates the realization of assets and satisfaction of liabilities in the normal course of business. The financial statements do not include any adjustments to reflect the possible future effects on the recoverability and classification of recorded asset amounts or the amounts and classification of liabilities that might result should the Company be unable to continue as a going concern.

Significant Accounting Policies

Significant Accounting Policies	9 Months Ended
	Sep. 30, 2019
Accounting Policies [Abstract]
Significant Accounting Policies	2. Significant Accounting Policies Basis of Presentation The Company’s financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“U.S. GAAP”). Unaudited Interim Financial Information The accompanying balance sheet as of September 30, 2019, statements of operations for the three and nine months ended September 30, 2019 and 2018, statements of stockholders’ equity for the three and nine months ended September 30, 2019 and 2018 and statements of cash flows for the nine months ended September 30, 2019 and 2018 are unaudited. The unaudited interim financial statements have been prepared on the same basis as the annual financial statements and, in the opinion of management, reflect all adjustments, which include normal recurring adjustments, necessary for the fair presentation of the Company’s financial position as of September 30, 2019, its results of its operations for the three and nine months ended September 30, 2019 and 2018, its changes in stockholders’ equity for the three and nine months ended September 30, 2019 and 2018 and its cash flows for the nine months ended September 30, 2019 and 2018. The financial data and other information disclosed in these notes related to the three and nine months ended September 30, 2019 and 2018 are unaudited. The results for the nine months ended September 30, 2019 are not indicative of results to be expected for the year ending December 31, 2019, any other interim periods or any future year or period. These unaudited financial statements should be read in conjunction with the audited financial statements and related footnotes, which are included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2018. Use of Estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make 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 reported amounts of income and expenses during the reporting periods. Significant items subject to such estimates and assumptions include the accounting for useful lives to calculate depreciation and amortization, clinical expense accruals, share-based compensation expense and income tax valuation allowance. Actual results could differ from these estimates. Research and Development Costs Research and development costs are charged to expense as incurred and include: • employee-related expenses, including salaries, benefits, travel and share-based compensation expense for research and development personnel; • expenses incurred under agreements with contract research organizations, contract manufacturing organizations and consultants that conduct clinical trials and preclinical studies; • costs associated with nonclinical and clinical development activities; • costs associated with submitting regulatory approval applications for the Company’s product candidates; • costs associated with training physicians on the suprachoroidal injection procedure and educating and providing them with appropriate product candidate information; • costs associated with technology and intellectual property licenses; • costs for the Company’s research and development facility; and • depreciation expense for assets used in research and development activities. Costs for certain development activities, such as clinical trials, are recognized based on an evaluation of the progress to completion of specific tasks using data such as patient enrollment, clinical site activations, or information provided to the Company by its vendors on their actual costs incurred. Payments for these activities are based on the terms of the individual arrangements, which may differ from the patterns of costs incurred, and are reflected in the financial statements as prepaid or accrued expense. Share-Based Compensation Compensation cost related to share-based awards granted to employees is measured based on the estimated fair value of the award at the grant date. The Company estimates the fair value of stock options using a Black-Scholes option pricing model. Compensation expense for options granted to non-employees is determined as the fair value of consideration received or the fair value of the equity instruments issued, whichever is more reliably measured. The fair value of restricted stock units granted is measured based on the market value of the Company’s common stock on the date of grant. Share-based compensation costs are expensed on a straight-line basis over the relevant vesting period. Compensation cost related to shares purchased through the Company’s employee stock purchase plan, which is considered compensatory, is based on the estimated fair value of the shares on the offering date, including consideration of the discount and the look back period. The Company estimates the fair value of the shares using a Black-Scholes option pricing model. Compensation expense is recognized over the six-month withholding period prior to the purchase date. All share-based compensation costs are recorded in general and administrative or research and development costs in the statements of operations based upon the underlying employees’ roles within the Company. Cash Equivalents Cash equivalents consist of short-term, highly liquid investments with an original term of three months or less at the date of purchase. Short-Term Investments Short-term investments are investments with original maturities of between 90 and 365 days when purchased and are comprised of commercial paper and treasury bills. The Company classifies its short-term investments as available-for-sale securities. Short-term investments are recorded at fair value and unrealized gains and losses are recorded within interest income. In addition, the Company evaluates the short-investments with unrealized losses to determine whether such losses are other-than-temporary. Concentration of Credit Risk Arising From Cash Deposits in Excess of Insured Limits The Company maintains its cash in bank deposits that at times may exceed federally insured limits. The Company has not experienced any loss in such accounts. The Company believes it is not exposed to any significant risks with respect to its cash balances. Recent Accounting Pronouncements In February 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2016-02, Leases (ASC 842), Leases, Targeted Improvements In June 2018, the FASB issued ASU 2018-07, Compensation-Stock Compensation: Improvements to Nonemployee Shared-Based Payment Accounting The Company adopted ASU 2018-07 effective January 1, 2019, and the adoption did not have a material impact on its financial statements and related disclosures.

Property and Equipment, Net

Property and Equipment, Net	9 Months Ended
	Sep. 30, 2019
Property Plant And Equipment [Abstract]
Property and Equipment, Net	3. Property and Equipment, Net Property and equipment, net consisted of the following (dollar amounts in thousands): Estimated Useful Lives (Years) September 30, 2019 December 2018 Furniture and fixtures 5 $ 400 $ 382 Machinery and equipment 5 121 121 Computer equipment 3 19 19 Leasehold improvements Lesser of useful life remaining lease term 684 677 1,224 1,199 Less: Accumulated depreciation (569 ) (409 ) $ 655 $ 790

Accrued Liabilities

Accrued Liabilities	9 Months Ended
	Sep. 30, 2019
Payables And Accruals [Abstract]
Accrued Liabilities	4. Accrued Liabilities Accrued liabilities consisted of the following (in thousands): September 30, December 2019 2018 Accrued research and development $ 403 $ 1,263 Accrued employee costs 1,950 1,191 Accrued marketing 31 47 Accrued professional fees 178 63 Accrued interest payable — 76 Accrued expense 136 283 $ 2,698 $ 2,923

Long-Term Debt

Long-Term Debt	9 Months Ended
	Sep. 30, 2019
Debt Disclosure [Abstract]
Long-Term Debt	5. Long-Term Debt Loan and Security Agreements In September 2016, the Company entered into an amended and restated loan and security agreement, which was subsequently amended on October 31, 2017 (as amended, the “1 st st Under the terms of the 1 st st st On May 14, 2018, the Company entered into a second amended and restated loan and security agreement (the “2 nd st nd nd The Company borrowed an initial tranche of $10.0 million on May 14, 2018, of which $7.0 million was used to repay all amounts outstanding under the 1 st Of the remaining $10.0 million under the 2 nd As of September 30, 2019, the Company was required to pay accrued interest only on the $10 million borrowed under the 2 nd followed by consecutive equal monthly payments of principal and interest in arrears continuing through the maturity date of October 1, 2022 2 The borrowings under the 2 nd On October 18, 2019, the Company entered into the 3 rd rd rd Interest expense on the borrowings under the loan agreements described above was $223,000 and $220,000 for the three months ended September 30, 2019 and 2018, respectively, and $676,000 and $566,000 for the nine months ended September 30, 2019 and 2018, respectively. Accretion of the scheduled final payment was $47,000 for each of the three months ended September 30, 2019 and 2018, and $141,000 and $107,000 for the nine months ended September 30, 2019 and 2018, respectively. Accretion of the deferred debt issuance costs was $16,000 for each of the three months ended September 30, 2019 and 2018, and $47,000 and $95,000 for the nine months ended September 30, 2019 and 2018, respectively. As of September 30, 2019, the scheduled payments for the 2nd A&R Loan Agreement, as amended, and the scheduled final payment in 2022, were as follows (in thousands): Year Ending December 31, Principal Interest and Final Total 2019 $ 5,000 $ 107 $ 5,107 2020 1,333 392 1,725 2021 2,000 234 2,234 2022 1,667 405 2,072 $ 10,000 $ 1,138 $ 11,138

Common Stock

Common Stock	9 Months Ended
	Sep. 30, 2019
Equity [Abstract]
Common Stock	6. Common Stock The Company’s amended and restated certificate of incorporation authorizes the Company to issue 100,000,000 shares of $0.001 par value common stock. As of September 30, 2019 and December 31, 2018, there were 41,149,781 and 32,119,227 shares of common stock outstanding, respectively.

Stock Purchase Warrants

Stock Purchase Warrants	9 Months Ended
	Sep. 30, 2019
Stock Purchase Warrants [Abstract]
Stock Purchase Warrants	7. Stock Purchase Warrants In September 2016, in connection with the 1 st Long-Term Debt .

Share-Based Compensation

Share-Based Compensation	9 Months Ended
	Sep. 30, 2019
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Share-Based Compensation	8. Share-Based Compensation Share-based compensation is accounted for in accordance with the provisions of ASC 718, Compensation-Stock Compensation Stock Options The Company has granted stock option awards to employees, directors and consultants from its 2011 Stock Incentive Plan (the “2011 Plan”) and its 2016 Equity Incentive Plan (the “2016 Plan”). The estimated fair value of options granted is determined as of the date of grant using the Black-Scholes option pricing model. The resulting fair value is recognized ratably over the requisite service period, which is generally the vesting period of the awards. Share-based compensation expense for options granted under the 2011 Plan and the 2016 Plan is reflected in the statements of operations as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 Research and development $ 243 $ 491 $ 1,066 $ 1,365 General and administrative 543 791 2,166 2,246 Total $ 786 $ 1,282 $ 3,232 $ 3,611 The following table summarizes the activity related to stock options during the nine months ended September 30, 2019: Weighted Number of Average Shares Exercise Price Options outstanding at December 31, 2018 3,463,096 $ 6.62 Granted 1,892,600 1.26 Exercised (16,362 ) 0.40 Forfeited (1,146,450 ) 5.00 Options outstanding at September 30, 2019 4,192,884 4.67 Options exercisable at December 31, 2018 1,583,749 5.63 Options exercisable at September 30, 2019 2,204,649 5.61 As of September 30, 2019, the Company had $5.0 million of unrecognized compensation expense related to unvested stock options, which is expected to be recognized over a weighted average period of 2.4 years. Restricted Stock Units The Company has granted restricted stock units (“RSUs”) to employees from the 2016 Plan. The shares underlying the RSU awards have vesting terms of eight months to two years from the date of grant subject to the employees’ continuous service and subject to accelerated vesting in specified circumstances. The fair value of the RSUs granted is measured based on the market value of the Company’s common stock on the date of grant and is recognized ratably over the requisite service period, which is generally the vesting period of the awards. The following table summarizes the activity related to RSUs during the nine months ended September 30, 2019: Weighted Number of Average Shares Exercise Price Non-vested RSUs outstanding at December 31, 2018 — $ — Granted 1,339,300 0.88 Vested (20,000 ) 1.09 Non-vested RSUs outstanding at September 30, 2019 1,319,300 0.88 The Company recorded $45,000 and $0.2 million of share-based compensation expense for the three and nine months ended September 30, 2019, respectively, for the RSUs. As of September 30, 2019, the Company had $1.0 million of unrecognized compensation expense related to the RSUs, which is expected to be recognized over a weighted average period of 1.4 years. Employee Stock Purchase Plan In January 2016, the Company’s board of directors adopted and approved, and in January 2016 the Company’s stockholders approved, the Clearside Biomedical, Inc. 2016 Employee Stock Purchase Plan (the “2016 ESPP”) which became effective on June 1, 2016. The first offering period for the 2016 ESPP commenced January 1, 2017. The 2016 ESPP is considered a compensatory plan and the fair value of the discount and the look-back period are estimated using the Black-Scholes option pricing model and expense is recognized over the six month withholding period prior to the purchase date. The Company has issued a total of 39,539 shares of common stock purchased under the 2016 ESPP. The Company has recorded $2,000 and $4,000 of share-based compensation expense for the three months ended September 30, 2019 and 2018, respectively, and $15,000 and $12,000 for the nine months ended September 30, 2019 and 2018, respectively, in the statements of operations for the estimated number of shares to be purchased on the next purchase date following the conclusion of the applicable reporting period.

Commitment and Contingencies

Commitment and Contingencies	9 Months Ended
	Sep. 30, 2019
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	9. Commitments and Contingencies Lease Commitment Summary In November 2016, the Company signed an office lease agreement to lease approximately 20,000 square feet of office space in Alpharetta, Georgia for its corporate headquarters. The lease agreement is for a 6.5 year term with a renewal option for one additional five-year term. Rental payments are $35,145 per month subject to an increase of 3% per year. Rent expense under this lease is recognized on a straight-line basis over the term of the lease. In addition, the lease agreement requires payment of the pro-rata share of the annual operating expenses associated with the premises. The Company relocated to this space in March 2017. In August 2018, the Company signed an office lease agreement to lease approximately 3,500 square feet of office space in Berkeley, California for its commercial operations. The lease agreement is for a two-year term with a renewal option for an additional one-year term. The Company has determined that it will not exercise the renewal option for the Berkeley lease. Rental payments are $12,775 per month subject to a 3% increase per year. Rent expense under this lease is recognized on a straight-line basis over the term of the lease. The Company will pay a pro-rata share of the annual operating expenses associated with the premises. The Company’s operating leases included on the balance sheet are as follows (in thousands): September 30, 2019 Operating lease right-of-use asset $ 806 Liabilities Current portion of operating lease liabilities $ 483 Operating lease liabilities 961 Total operating lease liabilities $ 1,444 The Company recognizes a right-of-use asset for the right to use the underlying asset for the lease term, and a lease liability, which represents the present value of the Company’s obligation to make payments over the lease term. The renewal option is not included in the calculation of the right-of-use asset and the lease liabilities as the Company has not yet determined if the Alpharetta, Georgia lease will be renewed. The present value of the lease payments is calculated using an incremental borrowing rate as the Company’s leases do not provide an implicit interest rate. At September 30, 2019, the Company’s weighted average discount rate was 5.3% and the weighted average lease term was 2.4 years. Total future undiscounted minimum lease payments were as follows at September 30, 2019 (in thousands): Year Ending December 31, 2019 $ 157 2020 574 2021 496 2022 511 2023 393 Total minimum lease payments $ 2,131 Equipment leases with an initial term of 12 months or less are not recorded with operating lease liabilities. The Company recognizes expense for these on a straight-line basis over the lease term. The equipment leases were deemed to be immaterial. Rent expense was $100,000 and $79,000 for the three months ended September 30, 2019 and 2018, respectively, and $300,000 and $195,000 for the nine months ended September 30, 2019 and 2018, respectively. Cash payments included in operating activities on the statement of cash flows for operating lease liabilities were $386,000 for the nine months ended September 30, 2019. Contract Service Providers In the course of the Company’s normal business operations, it has agreements with contract service providers to assist in the performance of its research and development, clinical research and manufacturing. Substantially all of these contracts are on an as needed basis.

Collaboration Agreements

Collaboration Agreements	9 Months Ended
	Sep. 30, 2019
Collaboration Agreements [Abstract]
Collaboration Agreements	10. Collaboration Agreements The Company has periodically entered into other short-term collaboration agreements, generally with performance obligations of one to two months, to evaluate the potential use of its proprietary SCS Microinjector with third-party product candidates for the treatment of various diseases. Funds received from these collaboration agreements are recognized as revenue over the term of the agreement. The Company recorded $141,000 and $231,000 of revenue from these collaboration agreements during the three and nine months ended September 30, 2019, respectively. In addition, the Company recorded $0.4 million of deferred revenue in other current liabilities from these collaboration agreements as of September 30, 2019.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2019
Fair Value Disclosures [Abstract]
Fair Value Measurements	11. Fair Value Measurements The Company records certain financial assets and liabilities at fair value in accordance with the provisions of ASC Topic 820, Fair Value Measurements and Disclosures • Level 1—Unadjusted quoted prices in active, accessible markets for identical assets or liabilities. • Level 2—Other inputs that are directly or indirectly observable in the marketplace. • Level 3—Unobservable inputs that are supported by little or no market activity. The fair value hierarchy also requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. The Company’s material financial instruments at September 30, 2019 and December 31, 2018 consisted primarily of cash and cash equivalents, short-term investments and long-term debt. The fair values of cash and cash equivalents, other current assets and accounts payable approximate their respective carrying values due to the short term nature of these instruments and are classified as Level 1 in the fair value hierarchy. The fair value of long-term debt approximates the carrying value due to variable interest rates that correspond to market rates and is classified as Level 1 in the fair value hierarchy. The Company has determined its short-term investments, comprised of commercial paper, to be Level 2 in the fair value hierarchy. The fair value was determined using a market approach, based on prices and other relevant information generated by market transactions involving similar assets. The short-term investments consist of investments with original maturity dates from date of acquisition of 90 to 365 days and are classified as available-for-sale. There were no significant transfers between Levels 1, 2 and 3 during the nine months ended September 30, 2019 and the year ended December 31, 2018. The following tables summarize the fair value of financial assets that are measured at fair value and the classification by level of input within the fair value hierarchy (in thousands): September 30, 2019 Level 1 Level 2 Level 3 Recorded Value Financial Assets: Cash and money markets $ 22,551 $ — $ — $ 22,551 Restricted cash money market 360 — — 360 Total financial assets $ 22,911 $ — $ — $ 22,911 December 31, 2018 Level 1 Level 2 Level 3 Recorded Value Financial Assets: Cash and money markets $ 8,042 $ — $ — $ 8,042 Restricted cash money market 360 — — 360 Treasury bills 7,490 — — 7,490 Commercial paper — 25,346 — 25,346 Total financial assets $ 15,892 $ 25,346 $ — $ 41,238

Net Loss per Share

Net Loss per Share	9 Months Ended
	Sep. 30, 2019
Earnings Per Share [Abstract]
Net Loss Per Share	12. Net Loss Per Share Basic net loss per share is calculated by dividing the net loss by the weighted average number of shares of common stock outstanding for the period, without consideration of the dilutive effect of potential common stock equivalents. Diluted net loss per share gives effect to all dilutive potential shares of common stock outstanding during this period. For all periods presented, the Company’s potential common stock equivalents, which included stock options and stock purchase warrants, have been excluded from the computation of diluted net loss per share as their inclusion would have the effect of reducing the net loss per share. Therefore, the denominator used to calculate both basic and diluted net loss per share is the same in all periods presented. The Company’s potential common stock equivalents that have been excluded from the computation of diluted net loss per share for all periods presented because of their antidilutive effect consisted of the following: Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 Outstanding stock options 4,192,884 3,220,500 4,192,884 3,220,500 Non-vested restricted stock units 1,319,300 — 1,319,300 — Stock purchase warrants 29,796 29,796 29,796 29,796 5,541,980 3,250,296 5,541,980 3,250,296

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2019
Subsequent Events [Abstract]
Subsequent Events	13. Subsequent Events License Agreement On October 22, 2019, the Company entered into the License Agreement with Bausch. Pursuant to the License Agreement, the Company has granted an exclusive license to Bausch to develop, manufacture, distribute, promote, market and commercialize XIPERE using the Company’s proprietary microneedle (the “Device”), as well as specified other steroids, corticosteroids and NSAIDs in combination with the Device (“Other Products”), subject to specified exceptions, in the United States and Canada for the treatment of ophthalmology indications, including non-infectious uveitis. Pursuant to the License Agreement, Bausch made an upfront payment of $5.0 million, which is subject to a refund if the License Agreement is terminated in specified circumstances. In addition, Bausch has agreed to make additional payments of up to $15.0 million upon the achievement of specified pre-launch development and regulatory milestones and up to an aggregate of $56.0 million in additional milestone payments upon the achievement of (i) specified regulatory approvals for specified additional indications of XIPERE and (ii) specified levels of annual net sales (as defined in the License Agreement). Further, during the applicable royalty term, the Company will also be entitled to receive tiered royalties at increasing percentages, from the high-teens to twenty percent, based on the achievement of certain annual net sales thresholds in the United States and Canada, as well as a lower royalty on annual net sales of Other Products, in each case subject to reductions in specified circumstances; provided that the Company will not receive any royalties on the first $30.0 million of cumulative net sales of all products. The Company is responsible for all development expenses for XIPERE until the Company’s New Drug Application (“NDA”) for XIPERE NDA Amendments to Loan and Security Agreement On October 18, 2019, the Company entered into a 3 rd the 3 rd Long-Term Debt ). On October 18, 2019, the Company entered into a Consent and Fourth Amendment to the 2 nd Agreement (the “4 th th Option and License Agreement On August 29, 2019, the Company entered into an option and license agreement with REGENXBIO, Inc. (“REGENXBIO”) pursuant to which the Company granted REGENXBIO an exclusive option to enter into a commercial license agreement (the “Option”) granting REGENXBIO an exclusive, worldwide and sublicensable license to the Company’s SCS Microinjector for the delivery of adeno-associated virus-based gene therapies for the treatment of wet age-related macular degeneration, diabetic retinopathy and other conditions for which anti-vascular endothelial growth factor

Significant Accounting Polici_2

Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2019
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The Company’s financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“U.S. GAAP”).
Unaudited Interim Financial Information	Unaudited Interim Financial Information The accompanying balance sheet as of September 30, 2019, statements of operations for the three and nine months ended September 30, 2019 and 2018, statements of stockholders’ equity for the three and nine months ended September 30, 2019 and 2018 and statements of cash flows for the nine months ended September 30, 2019 and 2018 are unaudited. The unaudited interim financial statements have been prepared on the same basis as the annual financial statements and, in the opinion of management, reflect all adjustments, which include normal recurring adjustments, necessary for the fair presentation of the Company’s financial position as of September 30, 2019, its results of its operations for the three and nine months ended September 30, 2019 and 2018, its changes in stockholders’ equity for the three and nine months ended September 30, 2019 and 2018 and its cash flows for the nine months ended September 30, 2019 and 2018. The financial data and other information disclosed in these notes related to the three and nine months ended September 30, 2019 and 2018 are unaudited. The results for the nine months ended September 30, 2019 are not indicative of results to be expected for the year ending December 31, 2019, any other interim periods or any future year or period. These unaudited financial statements should be read in conjunction with the audited financial statements and related footnotes, which are included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2018.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make 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 reported amounts of income and expenses during the reporting periods. Significant items subject to such estimates and assumptions include the accounting for useful lives to calculate depreciation and amortization, clinical expense accruals, share-based compensation expense and income tax valuation allowance. Actual results could differ from these estimates.
Research and Development Costs	Research and Development Costs Research and development costs are charged to expense as incurred and include: • employee-related expenses, including salaries, benefits, travel and share-based compensation expense for research and development personnel; • expenses incurred under agreements with contract research organizations, contract manufacturing organizations and consultants that conduct clinical trials and preclinical studies; • costs associated with nonclinical and clinical development activities; • costs associated with submitting regulatory approval applications for the Company’s product candidates; • costs associated with training physicians on the suprachoroidal injection procedure and educating and providing them with appropriate product candidate information; • costs associated with technology and intellectual property licenses; • costs for the Company’s research and development facility; and • depreciation expense for assets used in research and development activities. Costs for certain development activities, such as clinical trials, are recognized based on an evaluation of the progress to completion of specific tasks using data such as patient enrollment, clinical site activations, or information provided to the Company by its vendors on their actual costs incurred. Payments for these activities are based on the terms of the individual arrangements, which may differ from the patterns of costs incurred, and are reflected in the financial statements as prepaid or accrued expense.
Share-Based Compensation	Share-Based Compensation Compensation cost related to share-based awards granted to employees is measured based on the estimated fair value of the award at the grant date. The Company estimates the fair value of stock options using a Black-Scholes option pricing model. Compensation expense for options granted to non-employees is determined as the fair value of consideration received or the fair value of the equity instruments issued, whichever is more reliably measured. The fair value of restricted stock units granted is measured based on the market value of the Company’s common stock on the date of grant. Share-based compensation costs are expensed on a straight-line basis over the relevant vesting period. Compensation cost related to shares purchased through the Company’s employee stock purchase plan, which is considered compensatory, is based on the estimated fair value of the shares on the offering date, including consideration of the discount and the look back period. The Company estimates the fair value of the shares using a Black-Scholes option pricing model. Compensation expense is recognized over the six-month withholding period prior to the purchase date. All share-based compensation costs are recorded in general and administrative or research and development costs in the statements of operations based upon the underlying employees’ roles within the Company.
Cash Equivalents	Cash Equivalents Cash equivalents consist of short-term, highly liquid investments with an original term of three months or less at the date of purchase.
Short-Term Investments	Short-Term Investments Short-term investments are investments with original maturities of between 90 and 365 days when purchased and are comprised of commercial paper and treasury bills. The Company classifies its short-term investments as available-for-sale securities. Short-term investments are recorded at fair value and unrealized gains and losses are recorded within interest income. In addition, the Company evaluates the short-investments with unrealized losses to determine whether such losses are other-than-temporary.
Concentration of Credit Risk Arising From Cash Deposits in Excess of Insured Limits	Concentration of Credit Risk Arising From Cash Deposits in Excess of Insured Limits The Company maintains its cash in bank deposits that at times may exceed federally insured limits. The Company has not experienced any loss in such accounts. The Company believes it is not exposed to any significant risks with respect to its cash balances.
Recent Accounting Pronouncements	Recent Accounting Pronouncements In February 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2016-02, Leases (ASC 842), Leases, Targeted Improvements In June 2018, the FASB issued ASU 2018-07, Compensation-Stock Compensation: Improvements to Nonemployee Shared-Based Payment Accounting The Company adopted ASU 2018-07 effective January 1, 2019, and the adoption did not have a material impact on its financial statements and related disclosures.

Property and Equipment, Net (Ta

Property and Equipment, Net (Tables)	9 Months Ended
	Sep. 30, 2019
Property Plant And Equipment [Abstract]
Schedule of Property and Equipment, Net	Property and equipment, net consisted of the following (dollar amounts in thousands): Estimated Useful Lives (Years) September 30, 2019 December 2018 Furniture and fixtures 5 $ 400 $ 382 Machinery and equipment 5 121 121 Computer equipment 3 19 19 Leasehold improvements Lesser of useful life remaining lease term 684 677 1,224 1,199 Less: Accumulated depreciation (569 ) (409 ) $ 655 $ 790

Accrued Liabilities (Tables)

Accrued Liabilities (Tables)	9 Months Ended
	Sep. 30, 2019
Payables And Accruals [Abstract]
Schedule of Accrued Liabilities	Accrued liabilities consisted of the following (in thousands): September 30, December 2019 2018 Accrued research and development $ 403 $ 1,263 Accrued employee costs 1,950 1,191 Accrued marketing 31 47 Accrued professional fees 178 63 Accrued interest payable — 76 Accrued expense 136 283 $ 2,698 $ 2,923

Long-Term Debt (Tables)

Long-Term Debt (Tables)	9 Months Ended
	Sep. 30, 2019
Second Amended and Restated Loan and Security Agreement
Scheduled Payments for the Second Amended and Restated Loan and Security Agreement	As of September 30, 2019, the scheduled payments for the 2nd A&R Loan Agreement, as amended, and the scheduled final payment in 2022, were as follows (in thousands): Year Ending December 31, Principal Interest and Final Total 2019 $ 5,000 $ 107 $ 5,107 2020 1,333 392 1,725 2021 2,000 234 2,234 2022 1,667 405 2,072 $ 10,000 $ 1,138 $ 11,138

Share-Based Compensation (Table

Share-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Summary of Share-based Compensation Expense	Share-based compensation expense for options granted under the 2011 Plan and the 2016 Plan is reflected in the statements of operations as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 Research and development $ 243 $ 491 $ 1,066 $ 1,365 General and administrative 543 791 2,166 2,246 Total $ 786 $ 1,282 $ 3,232 $ 3,611
Summary of Activity Related to Stock Options	The following table summarizes the activity related to stock options during the nine months ended September 30, 2019: Weighted Number of Average Shares Exercise Price Options outstanding at December 31, 2018 3,463,096 $ 6.62 Granted 1,892,600 1.26 Exercised (16,362 ) 0.40 Forfeited (1,146,450 ) 5.00 Options outstanding at September 30, 2019 4,192,884 4.67 Options exercisable at December 31, 2018 1,583,749 5.63 Options exercisable at September 30, 2019 2,204,649 5.61
Restricted Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Summary of the Activity Related to RSUs	The following table summarizes the activity related to RSUs during the nine months ended September 30, 2019: Weighted Number of Average Shares Exercise Price Non-vested RSUs outstanding at December 31, 2018 — $ — Granted 1,339,300 0.88 Vested (20,000 ) 1.09 Non-vested RSUs outstanding at September 30, 2019 1,319,300 0.88

Commitment and Contingencies (T

Commitment and Contingencies (Tables)	9 Months Ended
	Sep. 30, 2019
Commitments And Contingencies Disclosure [Abstract]
Operating Leases Included on the Balance Sheet	The Company’s operating leases included on the balance sheet are as follows (in thousands): September 30, 2019 Operating lease right-of-use asset $ 806 Liabilities Current portion of operating lease liabilities $ 483 Operating lease liabilities 961 Total operating lease liabilities $ 1,444
Total Future Undiscounted Minimum Lease Payments	Total future undiscounted minimum lease payments were as follows at September 30, 2019 (in thousands): Year Ending December 31, 2019 $ 157 2020 574 2021 496 2022 511 2023 393 Total minimum lease payments $ 2,131

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2019
Fair Value Disclosures [Abstract]
Summary of Assets Measured at Fair Value	The following tables summarize the fair value of financial assets that are measured at fair value and the classification by level of input within the fair value hierarchy (in thousands): September 30, 2019 Level 1 Level 2 Level 3 Recorded Value Financial Assets: Cash and money markets $ 22,551 $ — $ — $ 22,551 Restricted cash money market 360 — — 360 Total financial assets $ 22,911 $ — $ — $ 22,911 December 31, 2018 Level 1 Level 2 Level 3 Recorded Value Financial Assets: Cash and money markets $ 8,042 $ — $ — $ 8,042 Restricted cash money market 360 — — 360 Treasury bills 7,490 — — 7,490 Commercial paper — 25,346 — 25,346 Total financial assets $ 15,892 $ 25,346 $ — $ 41,238

Net Loss per Share (Tables)

Net Loss per Share (Tables)	9 Months Ended
	Sep. 30, 2019
Earnings Per Share [Abstract]
Potential Common Stock Equivalents Excluded from Computation of Diluted Net Loss per Share	The Company’s potential common stock equivalents that have been excluded from the computation of diluted net loss per share for all periods presented because of their antidilutive effect consisted of the following: Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 Outstanding stock options 4,192,884 3,220,500 4,192,884 3,220,500 Non-vested restricted stock units 1,319,300 — 1,319,300 — Stock purchase warrants 29,796 29,796 29,796 29,796 5,541,980 3,250,296 5,541,980 3,250,296

The Company - Additional Inform

The Company - Additional Information (Details) - USD ($)	Oct. 22, 2019	Oct. 18, 2019	Jul. 13, 2017	Jun. 30, 2017	Sep. 30, 2019	Dec. 31, 2018	Sep. 30, 2018
Organization Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Entity incorporation date					May 26, 2011
Cash and cash equivalents					$ 22,551,000	$ 8,043,000	$ 15,841,000
Subsequent Event | Third Amended and Restated Loan and Security Agreement
Organization Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Repayment of outstanding amount under the loan agreement including fees		$ 5,000,000
Long term debt		10,000,000
Minimum balance requirement cash and cash equivalents		10,000,000
Debt instrument final payment		$ 340,441
Subsequent Event | Bausch Health Ireland Limited | License Agreement Terms
Organization Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Upfront payment received under the license agreement	$ 5,000,000
At-the-market sales agreement | Cowen and Company LLC | Common Stock
Organization Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Number of shares sold under facility					9,000,000
Net proceeds from issuance of stock					$ 10,300,000
At-the-market sales agreement | Cowen and Company LLC | Common Stock | Maximum
Organization Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Aggregate offering price, shares			$ 18,500,000	$ 50,000,000

Significant Accounting Polici_3

Significant Accounting Policies - Additional Information (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Jan. 01, 2019
Significant Accounting Policies [Line Items]
Short-term investments maturity start period	90 days
Short-term investments maturity end period	365 days
Recognition of a right-of use asset	$ 806
Recognition of a lease obligations	$ 1,444
ASU 2016-02
Significant Accounting Policies [Line Items]
Recognition of a right-of use asset		$ 1,000
Recognition of a lease obligations		$ 1,700

Property and Equipment, Net - S

Property and Equipment, Net - Schedule of Property and Equipment, Net (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Property Plant And Equipment [Line Items]
Property and Equipment, gross	$ 1,224	$ 1,199
Less: Accumulated depreciation	(569)	(409)
Property and equipment, net	655	790
Furniture and Fixtures
Property Plant And Equipment [Line Items]
Property and Equipment, gross	$ 400	382
Estimated Useful Lives (Years)	5 years
Machinery and Equipment
Property Plant And Equipment [Line Items]
Property and Equipment, gross	$ 121	121
Estimated Useful Lives (Years)	5 years
Computer Equipment
Property Plant And Equipment [Line Items]
Property and Equipment, gross	$ 19	19
Estimated Useful Lives (Years)	3 years
Leasehold Improvements
Property Plant And Equipment [Line Items]
Property and Equipment, gross	$ 684	$ 677
Estimated Useful Lives (Years)	Lesser of useful life or remaining lease term

Accrued Liabilities - Schedule

Accrued Liabilities - Schedule of Accrued Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Payables And Accruals [Abstract]
Accrued research and development	$ 403	$ 1,263
Accrued employee costs	1,950	1,191
Accrued marketing	31	47
Accrued professional fees	178	63
Accrued interest payable		76
Accrued expense	136	283
Accrued liabilities, current	$ 2,698	$ 2,923

Long-Term Debt - Additional Inf

Long-Term Debt - Additional Information (Details) - USD ($)	Oct. 18, 2019	May 14, 2018	Sep. 28, 2016	Sep. 30, 2016	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Mar. 31, 2018
Debt Instrument [Line Items]
Interest expense on borrowings					$ 223,000	$ 220,000	$ 676,000	$ 566,000
Accretion of scheduled final payment					47,000	47,000	141,000	107,000
Accretion of deferred debt issuance costs					16,000	$ 16,000	47,000	$ 95,000
Second Amended and Restated Loan and Security Agreement
Debt Instrument [Line Items]
Long term debt					10,000,000		$ 10,000,000
Third Amended and Restated Loan and Security Agreement
Debt Instrument [Line Items]
Debt Instrument, Payment Terms							On October 18, 2019, the Company entered into the 3rd Amendment with the Lenders. Pursuant to the 3rd Amendment, the Company repaid $5.0 million of the outstanding principal balance of the $10.0 million term loan. The Company did not pay any final payment or termination fees in connection with the $5.0 million prepayment. In addition, the Company and the Lenders agreed to modify the term loan repayment schedule. As amended, the term loan repayment schedule provides for interest only payments through April 30, 2020, or if the Company completes a specified financial milestone, October 31, 2020, followed by consecutive equal monthly payments of principal and interest in arrears continuing through the maturity date of October 1, 2022.
Third Amended and Restated Loan and Security Agreement | Subsequent Event
Debt Instrument [Line Items]
Long term debt	$ 10,000,000
Debt instrument, maturity date	Oct. 1, 2022
Repayment of outstanding amount under the loan agreement including fees	$ 5,000,000
Debt instrument final payment	340,441
Minimum balance requirement cash and cash equivalents	$ 10,000,000
Silicon Valley Bank, MidCap Funding XII Trust and MidCap Financial Trust | First Amended and Restated Loan and Security Agreement
Debt Instrument [Line Items]
Fixed interest rate				7.00%
Variable interest rate				0.50%
Debt instrument, description of variable rate basis							30-day U.S. LIBOR
Line of credit facility, maximum borrowing capacity				$ 15,000,000
Long term debt			$ 8,000,000
Line of credit facility, remaining borrowing capacity									$ 7,000,000
Line of credit facility, expiration date							Mar. 31, 2018
Debt Instrument, Payment Terms							The Company was required to pay accrued interest only on the outstanding $8.0 million balance through December 31, 2017, followed by 30 equal payments of principal and accrued interest.
Final payment during maturity					500,000		$ 500,000
Debt instrument, maturity date							Jun. 1, 2020
Repayment of outstanding amount under the loan agreement including fees			$ 5,300,000
Silicon Valley Bank, MidCap Funding XII Trust and MidCap Financial Trust | First Amended and Restated Loan and Security Agreement | Final Payment
Debt Instrument [Line Items]
Repayment of outstanding amount under the loan agreement including fees		$ 7,000,000
Silicon Valley Bank, MidCap Funding XII Trust and MidCap Financial Trust | First Amended and Restated Loan and Security Agreement | Prepayments Through May 31, 2020
Debt Instrument [Line Items]
Prepayment fee percentage of the original principal amount of the aggregate term loans				2.00%
Silicon Valley Bank, MidCap Funding III Trust and MidCap Financial Trust | Second Amended and Restated Loan and Security Agreement
Debt Instrument [Line Items]
Fixed interest rate		6.50%
Variable interest rate		1.89%
Debt instrument, description of variable rate basis							30-day U.S. LIBOR
Line of credit facility, maximum borrowing capacity		$ 20,000,000
Long term debt		10,000,000			$ 10,000,000		$ 10,000,000
Debt instrument, maturity date							Oct. 1, 2022
Final payment during maturity, percentage							5.50%
Silicon Valley Bank, MidCap Funding III Trust and MidCap Financial Trust | Second Amended and Restated Loan and Security Agreement | Term C Loan
Debt Instrument [Line Items]
Line of credit facility, remaining borrowing capacity description							Of the remaining $10.0 million under the 2nd A&R Loan Agreement, $5.0 million became available for draw but was not drawn by the Company, and the other $5.0 million is not available for draw.
Silicon Valley Bank, MidCap Funding III Trust and MidCap Financial Trust | Second Amended and Restated Loan and Security Agreement | Prepayment Prior to October 1, 2022
Debt Instrument [Line Items]
Prepayment fee percentage of the original principal amount					2.00%		2.00%
Silicon Valley Bank, MidCap Funding III Trust and MidCap Financial Trust | Second Amended and Restated Loan and Security Agreement, Initial Tranche
Debt Instrument [Line Items]
Long term debt		$ 10,000,000

Long-Term Debt - Scheduled Paym

Long-Term Debt - Scheduled Payments for the Second Amended and Restated Loan and Security Agreement (Details) - Second Amended and Restated Loan and Security Agreement $ in Thousands	Sep. 30, 2019USD ($)
Debt Instrument [Line Items]
Principal, 2019	$ 5,000
Principal, 2020	1,333
Principal, 2021	2,000
Principal, 2022	1,667
Principal	10,000
Interest and Final Payment, 2019	107
Interest and Final Payment, 2020	392
Interest and Final Payment, 2021	234
Interest and Final Payment, 2022	405
Interest and Final Payment	1,138
Total, 2019	5,107
Total, 2020	1,725
Total, 2021	2,234
Total, 2022	2,072
Total	$ 11,138

Common Stock - Additional Infor

Common Stock - Additional Information (Details) - $ / shares	Sep. 30, 2019	Dec. 31, 2018
Equity [Abstract]
Common stock, shares authorized	100,000,000	100,000,000
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares outstanding	41,149,781	32,119,227

Stock Purchase Warrants - Addit

Stock Purchase Warrants - Additional Information (Details) - Convertible Stock Warrant - First Amended and Restated Loan and Security Agreement - $ / shares	1 Months Ended	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2019
Class Of Warrant Or Right [Line Items]
Class of warrant Exercise	$ 10.74
Warrants expiration term	2026-09
Weighted average remaining life of warrants		7 years
Maximum
Class Of Warrant Or Right [Line Items]
Number of stock that can be purchased by each warrant	29,796

Share-Based Compensation - Summ

Share-Based Compensation - Summary of Share-based Compensation Expense (Details) - Stock Options - 2011 Stock Incentive Plan, 2016 Equity Incentive Plan - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share-based compensation expense	$ 786	$ 1,282	$ 3,232	$ 3,611
Research and Development
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share-based compensation expense	243	491	1,066	1,365
General and Administrative
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share-based compensation expense	$ 543	$ 791	$ 2,166	$ 2,246

Share-Based Compensation - Su_2

Share-Based Compensation - Summary of Activity Related to Stock Options (Details) - Stock Options	9 Months Ended
	Sep. 30, 2019$ / sharesshares	Dec. 31, 2018$ / sharesshares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Shares, Options outstanding, Beginning balance | shares	3,463,096
Number of Shares, Granted | shares	1,892,600
Number of Shares, Exercised | shares	(16,362)
Number of Shares, Forfeited | shares	(1,146,450)
Number of Shares, Options outstanding, Ending balance | shares	4,192,884
Number of Shares, Options exercisable | shares	2,204,649	1,583,749
Weighted Average Exercise Price, Options outstanding, Beginning balance | $ / shares	$ 6.62
Weighted Average Exercise Price, Granted | $ / shares	1.26
Weighted Average Exercise Price, Exercised | $ / shares	0.40
Weighted Average Exercise Price, Forfeited | $ / shares	5
Weighted Average Exercise Price, Options outstanding, Ending balance | $ / shares	4.67
Weighted Average Exercise Price, Options exercisable | $ / shares	$ 5.61	$ 5.63

Share-Based Compensation - Addi

Share-Based Compensation - Additional Information (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
2016 Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation expense	$ 2,000	$ 4,000	$ 15,000	$ 12,000
Common stock purchased			39,539
Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized compensation expense related to unvested stock options	5,000,000		$ 5,000,000
Expected to be recognized over a weighted average period			2 years 4 months 24 days
Restricted Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected to be recognized over a weighted average period			1 year 4 months 24 days
Share-based compensation expense	45,000		$ 200,000
Unrecognized compensation expense related to the RSUs	$ 1,000,000		$ 1,000,000

Share-Based Compensation - Su_3

Share-Based Compensation - Summary of the Activity Related to RSUs (Details) - Restricted Stock Units	9 Months Ended
	Sep. 30, 2019$ / sharesshares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Shares, Granted | shares	1,339,300
Number of Shares, Vested | shares	(20,000)
Non-vested units outstanding, Number of Shares, Ending balance | shares	1,319,300
Weighted Average Exercise Price, Granted | $ / shares	$ 0.88
Weighted Average Exercise Price, Vested | $ / shares	1.09
Non-vested units outstanding, Weighted Average Exercise Price, Ending balance | $ / shares	$ 0.88

Commitment and Contingencies -

Commitment and Contingencies - Additional Information (Details)	1 Months Ended		3 Months Ended		9 Months Ended
	Aug. 31, 2018USD ($)ft²	Nov. 30, 2016USD ($)ft²	Sep. 30, 2019USD ($)	Sep. 30, 2018USD ($)	Sep. 30, 2019USD ($)	Sep. 30, 2018USD ($)
Commitment And Contingencies [Line Items]
Lessee, operating lease, option to extend, description					The renewal option is not included in the calculation of the right-of-use asset and the lease liabilities as the Company has not yet determined if the Alpharetta, Georgia lease will be renewed.
Weighted average discount rate			5.30%		5.30%
Weighted average lease term			2 years 4 months 24 days		2 years 4 months 24 days
Rent expense			$ 100,000	$ 79,000	$ 300,000	$ 195,000
Cash payments included in operating activities for operating lease liabilities					$ 386,000
GEORGIA
Commitment And Contingencies [Line Items]
Area of office leased | ft²		20,000
Operating lease agreement term		6 years 6 months
Operating lease agreement renewal option term		5 years
Minimum monthly lease payments		$ 35,145
Percentage of increase per year		3.00%
CALIFORNIA
Commitment And Contingencies [Line Items]
Area of office leased | ft²	3,500
Operating lease agreement term	2 years
Operating lease agreement renewal option term	1 year
Minimum monthly lease payments	$ 12,775
Percentage of increase per year	3.00%

Commitment and Contingencies _2

Commitment and Contingencies - Operating Leases Included on the Balance Sheet (Details) $ in Thousands	Sep. 30, 2019USD ($)
Commitments And Contingencies Disclosure [Abstract]
Operating lease right-of-use asset	$ 806
Liabilities
Current portion of operating lease liabilities	483
Operating lease liabilities	961
Total operating lease liabilities	$ 1,444

Commitment and Contingencies _3

Commitment and Contingencies - Total Future Undiscounted Minimum Lease Payments (Details) $ in Thousands	Sep. 30, 2019USD ($)
Commitments And Contingencies Disclosure [Abstract]
2019	$ 157
2020	574
2021	496
2022	511
2023	393
Total minimum lease payments	$ 2,131

Collaboration Agreements - Addi

Collaboration Agreements - Additional Information (Detail)	3 Months Ended	9 Months Ended
	Sep. 30, 2019USD ($)	Sep. 30, 2019USD ($)
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenue	$ 141,000	$ 231,000
Minimum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Other short-term collaboration agreements performance obligations period		1 month
Maximum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Other short-term collaboration agreements performance obligations period		2 months
Other Current Liabilities
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Deferred revenue	400,000	$ 400,000
Collaboration Agreements
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenue	$ 141,000	$ 231,000

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Details) - USD ($)	9 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Fair Value Disclosures [Abstract]
Short-term investments maturity start period	90 days
Short-term investments maturity end period	365 days
Significant transfers between Levels 1, 2 and 3	$ 0	$ 0

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Assets Measured at Fair Value (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Financial Assets:
Total financial assets	$ 22,911	$ 41,238
Cash and Money Markets
Financial Assets:
Total financial assets	22,551	8,042
Restricted Cash Money Market
Financial Assets:
Total financial assets	360	360
Treasury Bills
Financial Assets:
Total financial assets		7,490
Commercial Paper
Financial Assets:
Total financial assets		25,346
Level 1
Financial Assets:
Total financial assets	22,911	15,892
Level 1 | Cash and Money Markets
Financial Assets:
Total financial assets	22,551	8,042
Level 1 | Restricted Cash Money Market
Financial Assets:
Total financial assets	$ 360	360
Level 1 | Treasury Bills
Financial Assets:
Total financial assets		7,490
Level 2
Financial Assets:
Total financial assets		25,346
Level 2 | Commercial Paper
Financial Assets:
Total financial assets		$ 25,346

Net Loss Per Share - Potential

Net Loss Per Share - Potential Common Stock Equivalents Excluded from Computation of Diluted Net Loss per Share (Details) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share	5,541,980	3,250,296	5,541,980	3,250,296
Outstanding Stock Options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share	4,192,884	3,220,500	4,192,884	3,220,500
Non-vested Restricted Stock Units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share	1,319,300		1,319,300
Stock Purchase Warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share	29,796	29,796	29,796	29,796

Subsequent Events - Additional

Subsequent Events - Additional Information (Details) - Subsequent Event - USD ($)	Oct. 29, 2019	Oct. 22, 2019	Oct. 18, 2019
Third Amended and Restated Loan and Security Agreement
Subsequent Event [Line Items]
Repayment of outstanding amount under the loan agreement including fees			$ 5,000,000
Long term debt			10,000,000
Minimum balance requirement cash and cash equivalents			10,000,000
Debt instrument final payment			$ 340,441
Commercial Arrangement | Maximum
Subsequent Event [Line Items]
Pre-launch milestone payments		$ 15,000,000
Additional milestone payments		56,000,000
License Arrangement | REGENXBIO, Inc.
Subsequent Event [Line Items]
Option fee payment	$ 2,000,000
Proceeds from option fee previously received	500,000
Milestone payments	34,000,000
Sales-based milestone payments	$ 102,000,000
Bausch Health Ireland Limited
Subsequent Event [Line Items]
Upfront payment		5,000,000
First cumulative net sales of products		$ 30,000,000