SI-BONE (SIBN) 10-Q 2 May 23 2023 Q1 Quarterly report Financial data

Cover

Cover - shares	3 Months Ended
	Mar. 31, 2023	Apr. 26, 2023
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2023
Document Transition Report	false
Entity File Number	001-38701
Entity Registrant Name	SI-BONE, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	26-2216351
Entity Address, Address Line One	471 El Camino Real
Entity Address, Address Line Two	Suite 101
Entity Address, City or Town	Santa Clara
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	95050
City Area Code	408
Local Phone Number	207-0700
Title of 12(b) Security	Common Stock, par value $0.0001 per share
Trading Symbol	SIBN
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		35,184,049
Entity Central Index Key	0001459839
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	Q1
Amendment Flag	false
Entity Filer Category	Non-accelerated Filer

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 22,969	$ 20,717
Short-term investments	62,997	76,573
Accounts receivable, net of allowance for credit losses of $450 and $400, respectively	22,600	20,674
Inventory	17,790	17,282
Prepaid expenses and other current assets	2,045	2,365
Total current assets	128,401	137,611
Property and equipment, net	16,629	15,564
Operating lease right-of-use assets	3,672	4,002
Other non-current assets	374	375
TOTAL ASSETS	149,076	157,552
Current liabilities:
Accounts payable	5,331	6,279
Accrued liabilities and other	9,896	13,511
Operating lease liabilities, current portion	1,401	1,388
Total current liabilities	16,628	21,178
Long-term borrowings	35,938	35,171
Operating lease liabilities, net of current portion	2,525	2,871
Other long-term liabilities	26	30
TOTAL LIABILITIES	55,117	59,250
Commitments and contingencies (Note 6)
STOCKHOLDERS’ EQUITY
Preferred stock, $0.0001 par value; 5,000,000 shares authorized; no shares issued and outstanding	0	0
Common stock, $0.0001 par value; 100,000,000 shares authorized; 35,106,163 and 34,731,577 shares issued and outstanding, respectively	3	3
Additional paid-in capital	461,886	455,172
Accumulated other comprehensive income	300	232
Accumulated deficit	(368,230)	(357,105)
TOTAL STOCKHOLDERS’ EQUITY	93,959	98,302
TOTAL LIABILITIES AND STOCKHOLDERS’ EQUITY	$ 149,076	$ 157,552

CONDENSED CONSOLIDATED BALANC_2

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 450	$ 400
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred stock authorized (in shares)	5,000,000	5,000,000
Preferred stock issued (in shares)	0	0
Preferred stock outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock authorized (in shares)	100,000,000	100,000,000
Common stock issued (in shares)	35,106,163	34,731,577
Common stock outstanding (in shares)	35,106,163	34,731,577

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Income Statement [Abstract]
Revenue	$ 32,708	$ 22,439
Cost of goods sold	5,924	2,983
Gross profit	26,784	19,456
Operating expenses:
Sales and marketing	27,313	25,605
Research and development	3,291	3,580
General and administrative	7,473	7,139
Total operating expenses	38,077	36,324
Loss from operations	(11,293)	(16,868)
Interest and other income (expense), net:
Interest income	932	73
Interest expense	(838)	(561)
Other income (expense), net	74	(54)
Net loss	(11,125)	(17,410)
Other comprehensive income (loss):
Changes in foreign currency translation	(22)	0
Unrealized gain (loss) on marketable securities	90	(248)
Comprehensive loss	$ (11,057)	$ (17,658)
Net loss per share, basic (in usd per share)	$ (0.32)	$ (0.52)
Net loss per share, diluted (in usd per share)	$ (0.32)	$ (0.52)
Weighted-average number of common shares used to compute basic net loss per share (in shares)	34,916,106	33,792,326
Weighted-average number of common shares used to compute diluted net loss per share (in shares)	34,916,106	33,792,326

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income	Accumulated Deficit
Stockholders' equity, beginning of period (in shares) at Dec. 31, 2021		33,674,085
Stockholders' equity, beginning of period at Dec. 31, 2021	$ 134,420	$ 3	$ 429,914	$ 352	$ (295,849)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon exercise of stock options, net of shares withheld (in shares)		34,798
Issuance of common stock upon exercise of stock options, net of shares withheld	169		169
Issuance of common stock upon vesting of restricted stock units (in shares)		163,480
Stock-based compensation	5,507		5,507
Foreign currency translation	0
Net unrealized gain (loss) on marketable securities	(248)			(248)
Net loss	(17,410)				(17,410)
Stockholders' equity, end of period (in shares) at Mar. 31, 2022		33,872,363
Stockholders' equity, end of period at Mar. 31, 2022	$ 122,438	$ 3	435,590	104	(313,259)
Stockholders' equity, beginning of period (in shares) at Dec. 31, 2022	34,731,577	34,731,577
Stockholders' equity, beginning of period at Dec. 31, 2022	$ 98,302	$ 3	455,172	232	(357,105)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon exercise of stock options, net of shares withheld (in shares)	120,266	120,266
Issuance of common stock upon exercise of stock options, net of shares withheld	$ 520		520
Issuance of common stock upon vesting of restricted stock units (in shares)		254,320
Stock-based compensation	6,194		6,194
Foreign currency translation	(22)			(22)
Net unrealized gain (loss) on marketable securities	90			90
Net loss	$ (11,125)				(11,125)
Stockholders' equity, end of period (in shares) at Mar. 31, 2023	35,106,163	35,106,163
Stockholders' equity, end of period at Mar. 31, 2023	$ 93,959	$ 3	$ 461,886	$ 300	$ (368,230)

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Cash flows from operating activities
Net loss	$ (11,125)	$ (17,410)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation	6,194	5,507
Depreciation and amortization	1,086	713
Accounts receivable credit losses	50	0	$ 150
Accretion (amortization) of discount on marketable securities	(615)	244
Amortization of debt issuance costs	81	51
Loss on disposal of property and equipment	190	31
Changes in operating assets and liabilities:
Accounts receivable	(2,019)	1,603
Inventory	(536)	(3,178)
Prepaid expenses and other assets	311	12
Accounts payable	(745)	2,086
Accrued liabilities and other	(3,625)	(3,171)
Net cash used in operating activities	(10,753)	(13,512)
Cash flows from investing activities
Maturities of marketable securities	30,000	25,000
Purchases of marketable securities	(15,718)	(45,334)
Purchases of property and equipment	(2,579)	(2,274)
Net cash provided by (used in) investing activities	11,703	(22,608)
Cash flows from financing activities
Proceeds from debt financing	36,000	0
Repayments of debt financing	(35,275)	0
Payments of debt issuance costs	(40)	0
Proceeds from the exercise of stock options	520	169
Net cash provided by financing activities	1,205	169
Effect of exchange rate changes on cash and cash equivalents	97	(139)
Net increase (decrease) in cash and cash equivalents	2,252	(36,090)
Cash and cash equivalents at
Beginning of period	20,717	63,419	63,419
End of period	22,969	27,329	$ 20,717
Supplemental disclosure of non-cash information
Unpaid purchases of property and equipment	$ 887	$ 241

The Company and Nature of Busin

The Company and Nature of Business	3 Months Ended
	Mar. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
The Company and Nature of Business	The Company and Nature of Business SI-BONE, Inc. (the “Company”) was incorporated in the state of Delaware on March 18, 2008 and is headquartered in Santa Clara, California. The Company is a medical device company that has pioneered a proprietary minimally invasive surgical implant system to fuse the sacroiliac joint for treatment of musculoskeletal disorders of the sacropelvic anatomy. The Company introduced its first generation iFuse implant in 2009 in the U.S., in 2010 in certain countries in the European Union, and in 2015 in certain countries in the rest of the world. The second generation iFuse implant, iFuse-3D, was introduced in 2017 followed by iFuse-TORQ in 2021 and iFuse Bedrock Granite in 2022. Risks and Uncertainties The Company is subject to uncertainties related to liquidity, the ability to meet covenants and access to funding for its capital needs as the financial service industry has experienced disruptions characterized by the bankruptcy, failure, collapse or sale of various financial institutions. The Company’s cash and cash equivalents are primarily invested in deposits and money market accounts with two major financial institutions in the U.S. Deposits in these banks may exceed the federally insured limits or any other insurance provided on such deposits, if any. The Company had accounts with Silicon Valley Bank (“SVB”). On March 10, 2023, California regulators shut down SVB and the FDIC was appointed as SVB’s receiver. On March 26, 2023, the FDIC announced that it had entered into a purchase and assumption agreement with First-Citizens Bank & Trust Company (“First-Citizens”) under which all deposits of the former Silicon Valley Bank were assumed by First-Citizens. First-Citizens acquired the rights as lender under the Company’s Loan and Security Agreement as amended. To date, the Company has not experienced any losses on its deposits of cash, cash equivalents and marketable securities and continues to have access to these funds. The Company is subject to continuing risk and uncertainties resulting from the COVID-19 pandemic. The COVID-19 pandemic has impacted our supply chain and also caused delays or cancellations of our procedures. Continuing or future outbreaks of COVID-19 or other public health concerns could contribute to health systems diverting resources to respond to COVID-19 which could lead to scheduling delays or cancellations of our procedures. Continuing or future outbreaks could also cause or exacerbate supply chain shortages. As such the Company's future results of operations and liquidity could be adversely impacted by a variety of factors related to uncertainties in the financial services industry and new or ongoing impacts of the COVID-19 pandemic, including those discussed in the section titled "Risk Factors" in this report. As of the date of issuance of these condensed consolidated financial statements, the extent to which the COVID-19 pandemic, economic disruption that has resulted from the pandemic and measures taken to stabilize economies during the pandemic, global supply chain issues and uncertainties of the financial services industry may materially impact the Company's financial condition, liquidity, or results of operations remains uncertain.

Summary of Significant Accounti

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2023
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Basis of Presentation and Principles of Consolidation The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States of America (“U.S. GAAP”) and applicable rules and regulations of the Securities and Exchange Commission (“SEC”) regarding interim financial reporting. As permitted under those rules, certain footnotes or other financial information that are normally required by U.S. GAAP have been condensed or omitted, and accordingly the balance sheet as of December 31, 2022 has been derived from the audited consolidated financial statements at that date but does not include all of the information required by GAAP for complete financial statements. These unaudited interim condensed consolidated financial statements have been prepared on the same basis as the Company’s annual financial statements and, in the opinion of management, reflect all adjustments that are necessary for a fair statement of the Company’s consolidated financial information. The results of operations for the three months ended March 31, 2023 are not necessarily indicative of the results to be expected for the year ending December 31, 2023 or for any other interim period or for any other future year. The accompanying condensed consolidated financial statements should be read in conjunction with the audited financial statements and related notes thereto for the year ended December 31, 2022 contained in the Company’s Annual Report on Form 10-K filed with the SEC on March 2, 2023. 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 as of the date of the financial statements and the reported amounts of revenue and expenses during the reporting period. Significant accounting estimates and management judgments reflected in the condensed consolidated financial statements primarily includes the fair value of performance-based restricted stock unit awards. Estimates are based on historical experience, where applicable and other assumptions believed to be reasonable by the management. Actual results could differ from those estimates. Significant Accounting Policies The Company’s significant accounting policies are disclosed in the Company’s Annual Report on Form 10-K for the year ended December 31, 2022. The Company updated the accounting policies related to the property and equipment and revenue recognition, as follows: Property and Equipment Construction in progress includes assets that have not yet been placed into service including the cost of individual components of an instrument tray. Once an instrument tray is placed into service, the Company transfers its carrying value into machinery and equipment and begins depreciating the cost of the instrument tray over its useful life. Leasehold improvements are amortized over the lesser of their useful lives or the life of the lease. Upon the sale or retirement of these assets, the cost and related accumulated depreciation are removed from the consolidated balance sheet and the resulting gain or loss is recognized in the consolidated statement of operations. Maintenance and repairs are charged to operations as incurred. Revenue Recognition The Company’s revenue is derived from the sale of its products to medical groups and hospitals through its direct sales force and third-party sales agents and resellers throughout the U.S. and Europe. The Company receives payment for its implants consumed during the surgery and does not receive additional or separate consideration for the use of the instrument tray furnished by the Company for the surgeon’s use. The Company identifies the instrument trays as a lease component and the implants as a non-lease component in its arrangements with its customers. The Company determines that the non-lease component is qualitatively predominant, and as such, elected the practical expedient to not separate the lease and non-lease components. Therefore, the overall arrangement is accounted for under Accounting Standards Codification (“ASC”) 606, Revenue from Contracts with Customers (“ASC 606”). In accordance with ASC 606, the Company recognizes revenue when control is transferred to the customer, in an amount that reflects the consideration the Company expects to be entitled to in exchange for the goods or services. Under the revenue recognition standard, the Company applies the following five step approach: (1) identify the contract with a customer, (2) identify the performance obligations in the contract, (3) determine the transaction price, (4) allocate the transaction price to the performance obligations in the contract, and (5) recognize revenue when a performance obligation is satisfied. As it relates to product sales where the Company's sales representative delivers the product at the point of implantation at the hospital or medical facilities, the Company continues to recognize the revenue upon completion of the procedure and authorization by the customer, net of rebates and price discounts. This represents the majority of the Company's consolidated revenue. The Company also generates a small portion of revenue from the sale of products through distributors and to certain hospital or medical facilities where the products are ordered in advance of a procedure. The performance obligation is the delivery of the products and therefore, revenue is recognized upon shipment to the customers, net of rebates and price discounts. The Company accounts for rebates and price discounts as a reduction to revenue, calculated based on the terms agreed to with the customer. Historically, there had been no significant price discounts. Sales prices are specified in either the customer contract or agreed price list, which is executed prior to the transfer of control to the customer. For certain hospitals and medical facilities, the Company has agreements in place consists of either a master services agreement or an agreed price list, which defines the terms and conditions of the arrangement, including the pricing information, payment terms and pertinent aspects of the relationship between the parties. The Company also has agreements in place with its distributors, which include standard terms that do not allow for payment contingent on resale of the product, obtaining financing, or other terms that could impact the distributor’s payment obligation. The Company's standard payment terms are generally net 30 to 90 days. Segments The Company's chief operating decision makers are the Chief Executive Officer (“CEO”) and Chief Financial Officer (“CFO”). The CEO and the CFO review financial information presented on a consolidated basis, accompanied by information about revenue by geographic region, for purposes of evaluating financial performance. The Company has one business activity and there are no segment managers who are held accountable for operations, operating results or plans for levels or components below the consolidated unit level. Accordingly, the Company has determined that it has a single reportable and operating segment structure . The Company derives substantially all of its revenue from sales to customers in the U.S. Revenue by geography is based on billing address of the customer. International revenue accounted for less than 10% of the total revenue during the periods presented. Long-lived assets held outside the U.S. are immaterial. Following table summarizes the Company's revenue by geography: Three Months Ended March 31, 2023 2022 (in thousands) United States $ 30,450 $ 20,367 International 2,258 2,072 $ 32,708 $ 22,439 Recent Accounting Pronouncements No recently issued accounting standards are expected to have a material impact on the Company’s consolidated financial statements.

Marketable Securities

Marketable Securities	3 Months Ended
	Mar. 31, 2023
Investments, Debt and Equity Securities [Abstract]
Marketable Securities	Marketable Securities All of the Company's marketable securities were available-for-sale and were classified based on their maturities. Marketable securities with remaining maturities at the date of purchase of three months or less are classified as cash equivalents. Short-term investments are securities that original maturity or remaining maturity is greater than three months and not more than twelve months. Long-term investments are securities for which the original maturity or remaining maturity is greater than twelve months. The table below summarizes the marketable securities: March 31, 2023 Amortized Cost Unrealized Gains Unrealized Losses Aggregate Fair Value (in thousands) Money market funds $ 15,602 $ — $ — $ 15,602 Cash equivalents 15,602 — — 15,602 U.S. treasury securities 35,978 7 (21) 35,964 Corporate bonds 2,945 — (7) 2,938 Commercial paper 18,265 — — 18,265 U.S. agency bonds 5,820 11 (1) 5,830 Short-term investments 63,008 18 (29) 62,997 Total marketable securities $ 78,610 $ 18 $ (29) $ 78,599 December 31, 2022 Amortized Cost Unrealized Gains Unrealized Losses Aggregate Fair Value (in thousands) Money market funds $ 8,002 $ — $ — $ 8,002 Cash equivalents 8,002 — — 8,002 U.S. treasury securities 48,636 4 (105) 48,535 U.S. agency bonds 2,918 3 — 2,921 Corporate bonds 2,914 — (3) 2,911 Commercial paper 22,206 — — 22,206 Short-term investments 76,674 7 (108) 76,573 Total marketable securities $ 84,676 $ 7 $ (108) $ 84,575 The amortized cost of the Company's available-for-sale securities approximates their fair value. Unrealized losses are generally due to interest rate fluctuations, as opposed to credit quality. However, the Company reviews individual securities that are in an unrealized loss position in order to evaluate whether or not they have experienced or are expected to experience credit losses. During the three months ended March 31, 2023 and 2022, unrealized gains and losses from the investments were not material and were not the result of a decline in credit quality. As a result, the Company did not recognize any credit losses related to its investments and that all unrealized gains and losses on available-for-sale securities are recorded in accumulated other comprehensive income (loss) on the condensed consolidated balance sheets as of March 31, 2023 and December 31, 2022. The Company elected to present accrued interest receivable separately from short-term and long-term investments on its condensed consolidated balance sheets. Accrued interest receivable was $0.1 million as of March 31, 2023, and was recorded in prepaid expenses and other current assets. The Company also elected to exclude accrued interest receivable from the estimation of expected credit losses on its marketable securities and reverse accrued interest receivable through interest income (expense) when amounts are determined to be uncollectible. The Company did not write off any accrued interest receivable as of March 31, 2023 or December 31, 2022.

Fair Value Measurement

Fair Value Measurement	3 Months Ended
	Mar. 31, 2023
Fair Value Disclosures [Abstract]
Fair Value Measurement	Fair Value Measurement Carrying amounts of certain of the Company’s financial instruments, including cash equivalents, accounts receivable, accounts payable and accrued liabilities, approximate fair value due to their relatively short maturities and market interest rates, if applicable. The carrying value of the Company’s long-term debt also approximates fair value based on management’s estimation that a current interest rate would not differ materially from the stated rate. There were no other financial assets and liabilities that require fair value hierarchy measurements and disclosures for the periods presented. The table below summarizes the fair value of the Company’s marketable securities measured at fair value on a recurring basis based on the three-tier fair value hierarchy: March 31, 2023 Level 1 Level 2 Level 3 Total (in thousands) Marketable securities Money market funds $ 15,602 $ — $ — $ 15,602 U.S. treasury securities 35,964 — — 35,964 Corporate bonds — 2,938 — 2,938 U.S. agency bonds — 5,830 — 5,830 Commercial paper — 18,265 — 18,265 Total marketable securities $ 51,566 $ 27,033 $ — $ 78,599 December 31, 2022 Level 1 Level 2 Level 3 Total (in thousands) Marketable securities Money market funds $ 8,002 $ — $ — $ 8,002 U.S. treasury securities 48,535 — — 48,535 U.S. agency bonds — 2,921 — 2,921 Corporate bonds — 2,911 — 2,911 Commercial paper — 22,206 — 22,206 Total marketable securities $ 56,537 $ 28,038 $ — $ 84,575

Balance Sheet Components

Balance Sheet Components	3 Months Ended
	Mar. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Balance Sheet Components	Balance Sheet Components Inventory As of March 31, 2023, inventory consisted of finished goods of $16.3 million and work-in-progress of $1.5 million. As of December 31, 2022, inventory consisted of finished goods of $15.6 million and work-in-progress and components of $1.7 million. Property and Equipment, net: March 31, 2023 December 31, 2022 (in thousands) Machinery and equipment $ 17,070 $ 14,920 Construction in progress 7,682 7,854 Computer and office equipment 1,139 976 Leasehold improvements 1,631 1,631 Furniture and fixtures 390 390 27,912 25,771 Less: Accumulated depreciation and amortization (11,283) (10,207) $ 16,629 $ 15,564 As of March 31, 2023, construction in progress pertains to the cost of individual components of a custom instrument set used for surgical placement of the Company's products that have not yet been placed into service of $4.0 million and construction costs related to the Company's lease for research and development and warehouse space in Santa Clara and software costs of $3.7 million. Depreciation expense was $1.1 million and $0.7 million for the three months ended March 31, 2023 and 2022, respectively. Accrued Liabilities and Other : March 31, 2023 December 31, 2022 (in thousands) Accrued compensation and related expenses $ 7,487 $ 11,365 Accrued royalty 996 818 Accrued professional services 652 355 Others 761 973 $ 9,896 $ 13,511 Accounts Receivable and Allowance for Credit Losses: The movement in the allowance for credit losses was as follows: March 31, 2023 December 31, 2022 (in thousands) Balance at beginning of period $ 400 $ 264 Provision 50 150 Write-offs — (14) Balance at end of period $ 450 $ 400

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2023
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Operating Leases The Company has a non-cancelable operating lease for an office building space, located in Santa Clara, California which expires in May 2025 and a building used for research and development and warehouse space in Santa Clara, California which expires in October 2026. The Company also has non-cancelable operating leases for its office building spaces in Gallarate, Italy and Knaresborough, United Kingdom, which expire in August 2027 and December 2025, respectively. The Company also leases vehicles under operating lease arrangements for certain of its personnel in Europe which expire at various times throughout 2023 to 2027. Supplemental information related to lease expense and valuation of the lease assets and lease liabilit ies are as follows: Three Months Ended 2023 2022 Operating lease expense $ 394 $ 409 Variable lease expense 76 104 Total lease expense $ 470 $ 513 Cash paid for amounts included in the measurement of operating lease liabilities $ 398 $ 408 Leased assets obtained in exchange for new operating lease liabilities $ 21 $ — March 31, 2023 December 31, 2022 Weighted average remaining lease term (in years) 2.83 3.05 Weighted average discount rate 5.77% 5.77% Future minimum lease payments under non-cancelable operating leases as of March 31, 2023 was as follows: Year Ending December 31, (in thousands) Remainder of 2023 $ 1,195 2024 1,517 2025 1,005 2026 530 2027 9 Thereafter — Total operating lease payments 4,256 Less: imputed interest (330) Total operating lease liabilities $ 3,926 As of March 31, 2023, the Company had no operating lease liabilities that had not commenced. Purchase Commitments and Obligations The Company has certain purchase commitments related to its inventory management with certain manufacturing suppliers wherein the Company is required to purchase the amounts forecasted in a blanket purchase order. The contractual obligations represent future cash commitments and liabilities under agreements with third parties and exclude orders for goods and services entered into in the normal course of business that are not enforceable or legally binding. These outstanding commitments amounted to $1.8 million and $0.8 million as of March 31, 2023 and December 31, 2022, respectively. Indemnification The Company enters into standard indemnification arrangements in the ordinary course of business. Pursuant to these arrangements, the Company indemnifies, holds harmless, and agrees to reimburse the indemnified parties for losses suffered or incurred by the indemnified party, in connection with any trade secret, copyright, patent or other intellectual property infringement claim by any third-party with respect to the Company’s technology. The term of these indemnification agreements is generally perpetual. The maximum potential amount of future payments the Company could be required to make under these agreements is not determinable because it involves claims that may be made against the Company in the future, but have not yet been made. The Company has entered into indemnification agreements with its directors and officers that may require the Company to indemnify its directors and officers against liabilities that may arise by reason of their status or service as directors or officers, other than liabilities arising from willful misconduct of the individual. The Company has not incurred costs to defend lawsuits or settle claims related to these indemnification agreements. No liability associated with such indemnifications has been recorded to date. Legal Contingencies

Borrowings

Borrowings	3 Months Ended
	Mar. 31, 2023
Debt Disclosure [Abstract]
Borrowings	Borrowings Term Loan The following table summarizes the outstanding borrowings from the term loan as of periods presented: March 31, 2023 December 31, 2022 (in thousands) Principal outstanding and final fee $ 36,720 $ 35,700 Less: Unamortized debt issuance costs (99) (73) Unaccreted value of final fee (683) (456) Outstanding debt, net of debt issuance costs and unaccreted value of final fee $ 35,938 $ 35,171 Classified as: Long-term borrowings $ 35,938 $ 35,171 The outstanding debt is related to a term loan pursuant to the Loan and Security Agreement dated August 12, 2021 (the “Effective Date”), entered into by the Company with Silicon Valley Bank (“SVB”). Pursuant the agreement, SVB provided an aggregate principal amount of $35.0 million to the Company (the “SVB Term Loan”). On January 6, 2023, the Company entered into a First Amendment to Loan and Security Agreement (the “Amendment”) with SVB, which amended the Company's SVB Term Loan pursuant to which the Company had a term loan facility in an aggregate principal amount of $35.0 million (the “Original Loan Agreement” and with the Amendment, collectively the “Amended Loan Agreement”). Upon entry into the Amended Loan Agreement, the Company borrowed $36.0 million pursuant to a term loan (the "Term Loan"), which was substantially used to repay in full the $35.0 million term loan facility outstanding under the Original Loan Agreement and secured a revolving credit facility in an aggregate principal amount of up to $15.0 million (the "Revolver"). On March 14, 2023 all of SVB’s assets and liabilities, including all of SVB’s rights as the lender pursuant to the Amended Loan Agreement, were assigned to Silicon Valley Bridge Bank. On March 27, 2023, all of Silicon Valley Bridge Bank’s assets and liabilities were assigned and assumed by First-Citizens Bank & Trust Company (“First-Citizens”). The Amended Loan Agreement also includes an uncommitted accordion term loan in an aggregate principal amount of up to $15.0 million, which accordion may be approved by First-Citizens solely in its discretion, upon the Company’s request. The Term Loan matures on December 1, 2027 (the “Term Loan Maturity Date”). Interest on the Term Loan will be payable monthly at a floating annual rate set at the greater of the prime rate as published in the Wall Street Journal plus 0.5% or 6.75%. Commencing on July 1, 2025, the Company will be required to make monthly principal Term Loan amortization payments. A final fee payment of 2% of the original principal amount of the Term Loan is due upon the earlier of the Term Loan Maturity Date, termination, acceleration by First-Citizens following an event of default, or prepayment of the Term Loan. The Company may elect to prepay the Term Loan in whole prior to the Term Loan Maturity Date subject to a prepayment fee equal to 2% of the principal amount of the Term Loan prepaid at such time. No prepayment fee would be due if the Term Loan is refinanced by First-Citizens. Pursuant to the terms of the Amended Loan Agreement, revolving loans may be borrowed, repaid and reborrowed until the maturity date, which will be July 6, 2025 (the "Revolver Maturity Date"). Borrowings under the Revolver are based on 80% of eligible domestic accounts receivable borrowing base. Interest on the outstanding balance of the Revolver will be payable monthly at a floating annual rate set at the greater of the prime rate as published in the Wall Street Journal or 6.25%. Interest on borrowings is due monthly and any principal balance is due on the Revolver Maturity Date, provided that when Revolver Advances are outstanding, in the event the Company does not maintain an adjusted quick ratio of at least 1.5 to 1.0, then falling below such threshold will allow First-Citizens to apply accounts receivable collections to outstanding Revolver borrowings. The Company will pay a total commitment fee of $187,500 on account of the Revolver payable in installments, but fully earned at close. The Company will also be required to pay a fee of $150,000 if it terminates the Amended Loan Agreement or Revolver prior to Revolver Maturity Date. No termination fee would be due if the Revolver is replaced with a new facility with First-Citizens. No amounts were outstanding under the Revolver as of March 31, 2023. The Company accounted for the Amended Loan Agreement as a debt modification. Accordingly, the remaining unamortized debt issuance costs related to the Original Loan Agreement together with any lender fees incurred in connection with the entry of the Amended Loan Agreement are amortized to interest expense using the straight-line method over the new term of the loan through December 2027. The effective interest rate related to the First-Citizens Term Loan for the three months ended March 31, 2023 and March 31, 2022 was 8.6% and 6.3%, respectively. The table below summarizes the future principal and final fee payments under the Fist-Citizens Term Loan as of March 31, 2023: Year ending December 31, (in thousands) Remainder of 2023 $ — 2024 — 2025 8,400 2026 14,400 2027 13,920 Total principal and final fee payments $ 36,720 The Amended Loan Agreement contains customary events of default, including bankruptcy, the failure to make payments when due, the occurrence of a material impairment on First-Citizens's security interest over the collateral, a material adverse change, the occurrence of a default under certain other indebtedness of the Company and its subsidiaries, the rendering of certain types of judgments against the Company and its subsidiaries, the revocation of certain government approvals, violation of covenants, and incorrectness of representations and warranties in any material respect. In addition, the Amended Loan Agreement contains a financial covenant which requires the Company to maintain, at all times when the Financial Covenant Measuring Period is in effect, certain net revenue levels as agreed upon by the Company and First-Citizens. If the Company does not comply with the various covenants under the Amended Loan Agreement and an event of default occurs under the Amended Loan Agreement, the interest rate on outstanding amounts can increase by 3% and First-Citizens may, subject to various customary cure rights, decline to provide additional advances under the Revolver, require the immediate payment of all amounts outstanding under the Amended Loan Agreement, and foreclose on all collateral.

Stock-Based Incentive Compensat

Stock-Based Incentive Compensation Plans	3 Months Ended
	Mar. 31, 2023
Share-Based Payment Arrangement [Abstract]
Stock-Based Incentive Compensation Plans	Stock-Based Incentive Compensation Plans Stock Options The table below summarizes the stock option activity for the three months ended March 31, 2023: Number of Weighted- Outstanding as of December 31, 2022 1,903,341 $8.82 Exercised (120,266) 4.33 Canceled and forfeited (15,284) 21.36 Outstanding as of March 31, 2023 1,767,791 10.23 As of March 31, 2023, the unrecognized compensation cost related to stock options is insignificant and is expected to be recognized over a period of approximately 0.4 years. There were no stock options granted during the three months ended March 31, 2023 and 2022. Early Exercise of Unvested Stock Options Early exercises of stock options under the Company's 2008 Stock Option Plan are subject to a right of repurchase by the Company of any unvested shares. The repurchase rights lapse over the original vesting period of the options. The Company accounts for the cash received in consideration for the early exercised options as a liability included in accrued liabilities, which is then reclassified to stockholders’ equity as the options vest. As of March 31, 2023 and December 31, 2022, the Company had no shares subject to repurchase. Restricted Stock Units (“RSUs”) RSUs are share awards that entitle the holder to receive freely tradable shares of the Company’s common stock upon vesting. RSUs generally vest over two ecognized compensation cost related to the RSUs was $41.5 million, which is expected to be recognized over a period of approximately 2.8 years. The Company granted performance-based restricted stock unit awards subject to market and service vesting conditions to certain executive officers under SI-BONE's 2018 Equity Incentive Plan (“PSUs”). The shares subject to PSUs vest over a three-year performance period. The actual number of PSUs that will vest in each measurement period will be determined by the Compensation Committee based on the Company’s total shareholder return (“TSR”) relative to the TSR of the Median Peer Companies (as defined in the award agreement). The grant date fair value of each stock award with a market condition was determined using the Monte Carlo valuation model. The table below summarizes the assumptions used to estimate the grant date fair value of the PSUs granted: Three Months Ended March 31, 2023 2022 Expected volatility of common stock 58.0% to 73.0% 48.9% to 58.7% Expected volatility of peer companies 33.0% to 141.0% 24.2% to 152.5% Correlation coefficient of peer companies (0.15) to 1.00 (0.13) to 1.00 Risk-free interest rate 3.9% to 5.0% 0.4% to 1.2% Dividend yield —% to 1.3% —% to 1.0% As of March 31, 2023, the unrecognized compensation cost related to the PSUs was $4.1 million, which is expected to be recognized over a period of approximately 2.4 years. The table below summarizes RSU and PSU activity for the three months ended March 31, 2023: RSUs PSUs Number of Shares Weighted Average Grant Date Fair Value Number of Shares Weighted Average Grant Date Fair Value Outstanding as of December 31, 2022 1,794,928 $22.72 155,596 $19.50 Granted 1,044,344 15.69 255,458 12.33 Vested (228,388) 22.97 (25,932) 19.50 Canceled and forfeited (86,107) 21.70 — — Outstanding as of March 31, 2023 2,524,777 19.82 385,122 14.74 Employee Stock Purchase Plan The Company’s 2018 Employee Stock Purchase Plan (the “ESPP”) allows eligible employees to purchase shares of the Company's common stock through payroll deductions at the price equal to 85% of the lesser of the fair market value of the stock as of the first date or the ending date of each six month offering period. The offering period generally commences in May and November. On March 26, 2020, the Company's Compensation Committee approved the amendment of the terms of future offerings under the ESPP which, among other things, increased the maximum number of shares that may be purchased on any single purchase date, provided for automatic enrollment in a new offering, and provided that the offering which commenced in May 2020 be twelve months in duration and consist of two purchase periods. The fair value of the ESPP shares is estimated using the Black-Scholes option pricing model, which is being amortized over the requisite service period. The Company did not issue any shares under ESPP for the three months ended March 31, 2023 and 2022. As of March 31, 2023 and December 31, 2022, total accumulated ESPP related employee payroll deductions amounted to $1.2 million and $0.3 million, respectively, which were included within accrued compensation and related expenses in the condensed consolidated balance sheets. Stock-Based Compensation The table below presents the detail of stock-based compensation expense amounts included in the condensed consolidated statements of operations: Three Months Ended 2023 2022 (in thousands) Cost of goods sold $ 137 $ 123 Sales and marketing 2,910 2,594 Research and development 752 633 General and administrative 2,395 2,157 $ 6,194 $ 5,507

Net Loss Per Share of Common St

Net Loss Per Share of Common Stock	3 Months Ended
	Mar. 31, 2023
Earnings Per Share [Abstract]
Net Loss Per Share of Common Stock	Net Loss Per Share of Common Stock The table below summarizes the computation of basic and diluted net loss per share: Three Months Ended March 31, 2023 2022 (in thousands, except share and per share data) Net loss $ (11,125) $ (17,410) Weighted-average shares used to compute basic and diluted net loss per share 34,916,106 33,792,326 Net loss per share, basic and diluted $ (0.32) $ (0.52) Because the Company has reported a net loss in all periods presented, outstanding stock options, restricted stock units, ESPP purchase rights and common stock warrants are anti-dilutive and therefore diluted net loss per common share is the same as basic net loss per common share for the periods presented. The following anti-dilutive common stock equivalents were excluded from the computation of diluted net loss per share for the periods presented: Three Months Ended March 31, 2023 2022 Stock options 1,767,791 1,963,360 Restricted stock units 2,909,899 2,309,284 ESPP purchase rights 134,226 61,264 Common stock warrants 118,122 118,122 4,930,038 4,452,030

Related Party Transaction

Related Party Transaction	3 Months Ended
	Mar. 31, 2023
Related Party Transactions [Abstract]
Related Party Transaction	Related Party Transaction On February 24, 2020, the Company entered into a joint development agreement (the “Development Agreement”) with SeaSpine Orthopedics Corporation (“SeaSpine”), which merged with Orthofix Medical, Inc., to develop a next generation device for sacropelvic fixation. Mr. Keith Valentine, who serves as the President, Chief Executive Officer and a member of the board of directors of SeaSpine, also serves as a member of the Company's Board of Directors since August 2015. On April 27, 2021, Addendum No.1 to the Development Agreement was entered into by and between the Company and SeaSpine to extend certain obligations as described under the Development Agreement to a consultant of the Company. Pursuant to the development plan, SeaSpine shall use reasonable efforts to assist in the development of the potential product offering, including licensing certain existing intellectual property to be incorporated into such product. Under the terms of the Development Agreement, the Company agreed to make monthly payments to SeaSpine to reimburse for full time resources employed by SeaSpine responsible to conduct the development activities. For the three months ended March 31, 2023, the Company did not incur any reimbursement charges from SeaSpine. For the three months ended March 31, 2022, the Company expensed approximately $6,000 of the reimbursement charges from SeaSpine. The reimbursement charges were recorded within research and development expense in the condensed consolidated statements of operations . Certain intellectual property developed pursuant to the project plan will be owned by the Company, certain intellectual property developed pursuant to the project plan will be owned by SeaSpine, and other intellectual property developed pursuant to the project plan will be jointly owned by SeaSpine and the Company. The Company also agreed to provide SeaSpine a royalty-free, worldwide, perpetual, non-exclusive license of certain of the Company's intellectual property incorporated into the product to be developed. The Company also agreed to pay SeaSpine a product royalty, in an amount specified in the Development Agreement, for each resulting product sold for a period of 10 years beginning on the initial market launch. The term of the Development Agreement shall continue until the expiration of all royalty terms, unless earlier terminated by either party, as provided for by the Development Agreement. The Company recorded $0.06 million of royalty for the three months ended March 31, 2023. No royalties were recorded for three months ended March 31, 2022.

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2023
Income Tax Disclosure [Abstract]
Income Taxes	Income TaxesIn determining quarterly provisions for income taxes, the Company uses the annual estimated effective tax rate applied to the actual year-to-date profit or loss, adjusted for discrete items arising in that quarter. The Company updates its estimate of its annual effective tax rate at the end of each quarterly period. The estimate takes into account annual forecasted income (loss) before income taxes, the geographic mix of income (loss) before income taxes and any significant permanent tax items. The Company did not have provision for income taxes for the three months ended March 31, 2023 and 2022. The Company continues to maintain a full valuation allowance against its net deferred tax assets due to the uncertainty surrounding realization of such assets. The Company accounts for the uncertainty in income taxes by utilizing a comprehensive model for the recognition, measurement, presentation and disclosure in financial statements of any uncertain tax positions that have been taken or are expected to be taken on an income tax return. There had been no changes in the estimated uncertain tax benefits recorded as of March 31, 2023

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2023
Accounting Policies [Abstract]
Basis of Presentation	The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States of America (“U.S. GAAP”) and applicable rules and regulations of the Securities and Exchange Commission (“SEC”) regarding interim financial reporting. As permitted under those rules, certain footnotes or other financial information that are normally required by U.S. GAAP have been condensed or omitted, and accordingly the balance sheet as of December 31, 2022 has been derived from the audited consolidated financial statements at that date but does not include all of the information required by GAAP for complete financial statements.
Principles of Consolidation	These unaudited interim condensed consolidated financial statements have been prepared on the same basis as the Company’s annual financial statements and, in the opinion of management, reflect all adjustments that are necessary for a fair statement of the Company’s consolidated financial information. The results of operations for the three months ended March 31, 2023 are not necessarily indicative of the results to be expected for the year ending December 31, 2023 or for any other interim period or for any other future year.
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 as of the date of the financial statements and the reported amounts of revenue and expenses during the reporting period. Significant accounting estimates and management judgments reflected in the condensed consolidated financial statements primarily includes the fair value of performance-based restricted stock unit awards. Estimates are based on historical experience, where applicable and other assumptions believed to be reasonable by the management. Actual results could differ from those estimates.
Property and Equipment	Property and Equipment Construction in progress includes assets that have not yet been placed into service including the cost of individual components of an instrument tray. Once an instrument tray is placed into service, the Company transfers its carrying value into machinery and equipment and begins depreciating the cost of the instrument tray over its useful life. Leasehold improvements are amortized over the lesser of their useful lives or the life of the lease. Upon the sale or retirement of these assets, the cost and related accumulated depreciation are removed from the consolidated balance sheet and the resulting gain or loss is recognized in the consolidated statement of operations. Maintenance and repairs are charged to operations as incurred.
Revenue Recognition	Revenue Recognition The Company’s revenue is derived from the sale of its products to medical groups and hospitals through its direct sales force and third-party sales agents and resellers throughout the U.S. and Europe. The Company receives payment for its implants consumed during the surgery and does not receive additional or separate consideration for the use of the instrument tray furnished by the Company for the surgeon’s use. The Company identifies the instrument trays as a lease component and the implants as a non-lease component in its arrangements with its customers. The Company determines that the non-lease component is qualitatively predominant, and as such, elected the practical expedient to not separate the lease and non-lease components. Therefore, the overall arrangement is accounted for under Accounting Standards Codification (“ASC”) 606, Revenue from Contracts with Customers (“ASC 606”). In accordance with ASC 606, the Company recognizes revenue when control is transferred to the customer, in an amount that reflects the consideration the Company expects to be entitled to in exchange for the goods or services. Under the revenue recognition standard, the Company applies the following five step approach: (1) identify the contract with a customer, (2) identify the performance obligations in the contract, (3) determine the transaction price, (4) allocate the transaction price to the performance obligations in the contract, and (5) recognize revenue when a performance obligation is satisfied. As it relates to product sales where the Company's sales representative delivers the product at the point of implantation at the hospital or medical facilities, the Company continues to recognize the revenue upon completion of the procedure and authorization by the customer, net of rebates and price discounts. This represents the majority of the Company's consolidated revenue. The Company also generates a small portion of revenue from the sale of products through distributors and to certain hospital or medical facilities where the products are ordered in advance of a procedure. The performance obligation is the delivery of the products and therefore, revenue is recognized upon shipment to the customers, net of rebates and price discounts. The Company accounts for rebates and price discounts as a reduction to revenue, calculated based on the terms agreed to with the customer. Historically, there had been no significant price discounts. Sales prices are specified in either the customer contract or agreed price list, which is executed prior to the transfer of control to the customer. For certain hospitals and medical facilities, the Company has agreements in place consists of either a master services agreement or an agreed price list, which defines the terms and conditions of the arrangement, including the pricing information, payment terms and pertinent aspects of the relationship between the parties. The Company also has agreements in place with its distributors, which include standard terms that do not allow for payment contingent on resale of the product, obtaining financing, or other terms that could impact the distributor’s payment obligation. The Company's standard payment terms are generally net 30 to 90 days.
Segments	Segments The Company's chief operating decision makers are the Chief Executive Officer (“CEO”) and Chief Financial Officer (“CFO”). The CEO and the CFO review financial information presented on a consolidated basis, accompanied by information about revenue by geographic region, for purposes of evaluating financial performance. The Company has one business activity and there are no segment managers who are held accountable for operations, operating results or plans for levels or components below the consolidated unit level. Accordingly, the Company has determined that it has a single reportable and operating segment structure .
Recently Adopted Accounting Standards and Recent Accounting Standards Not Yet Effective	Recent Accounting Pronouncements No recently issued accounting standards are expected to have a material impact on the Company’s consolidated financial statements.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	3 Months Ended
	Mar. 31, 2023
Accounting Policies [Abstract]
Schedule of Revenue by Geography	Following table summarizes the Company's revenue by geography: Three Months Ended March 31, 2023 2022 (in thousands) United States $ 30,450 $ 20,367 International 2,258 2,072 $ 32,708 $ 22,439

Marketable Securities (Tables)

Marketable Securities (Tables)	3 Months Ended
	Mar. 31, 2023
Investments, Debt and Equity Securities [Abstract]
Schedule of Marketable Securities	The table below summarizes the marketable securities: March 31, 2023 Amortized Cost Unrealized Gains Unrealized Losses Aggregate Fair Value (in thousands) Money market funds $ 15,602 $ — $ — $ 15,602 Cash equivalents 15,602 — — 15,602 U.S. treasury securities 35,978 7 (21) 35,964 Corporate bonds 2,945 — (7) 2,938 Commercial paper 18,265 — — 18,265 U.S. agency bonds 5,820 11 (1) 5,830 Short-term investments 63,008 18 (29) 62,997 Total marketable securities $ 78,610 $ 18 $ (29) $ 78,599 December 31, 2022 Amortized Cost Unrealized Gains Unrealized Losses Aggregate Fair Value (in thousands) Money market funds $ 8,002 $ — $ — $ 8,002 Cash equivalents 8,002 — — 8,002 U.S. treasury securities 48,636 4 (105) 48,535 U.S. agency bonds 2,918 3 — 2,921 Corporate bonds 2,914 — (3) 2,911 Commercial paper 22,206 — — 22,206 Short-term investments 76,674 7 (108) 76,573 Total marketable securities $ 84,676 $ 7 $ (108) $ 84,575

Fair Value Measurement (Tables)

Fair Value Measurement (Tables)	3 Months Ended
	Mar. 31, 2023
Fair Value Disclosures [Abstract]
Schedule of Marketable Securities Measured at Fair Value on Recurring Basis	The table below summarizes the fair value of the Company’s marketable securities measured at fair value on a recurring basis based on the three-tier fair value hierarchy: March 31, 2023 Level 1 Level 2 Level 3 Total (in thousands) Marketable securities Money market funds $ 15,602 $ — $ — $ 15,602 U.S. treasury securities 35,964 — — 35,964 Corporate bonds — 2,938 — 2,938 U.S. agency bonds — 5,830 — 5,830 Commercial paper — 18,265 — 18,265 Total marketable securities $ 51,566 $ 27,033 $ — $ 78,599 December 31, 2022 Level 1 Level 2 Level 3 Total (in thousands) Marketable securities Money market funds $ 8,002 $ — $ — $ 8,002 U.S. treasury securities 48,535 — — 48,535 U.S. agency bonds — 2,921 — 2,921 Corporate bonds — 2,911 — 2,911 Commercial paper — 22,206 — 22,206 Total marketable securities $ 56,537 $ 28,038 $ — $ 84,575

Balance Sheet Components (Table

Balance Sheet Components (Tables)	3 Months Ended
	Mar. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of Property and Equipment, Net	Property and Equipment, net: March 31, 2023 December 31, 2022 (in thousands) Machinery and equipment $ 17,070 $ 14,920 Construction in progress 7,682 7,854 Computer and office equipment 1,139 976 Leasehold improvements 1,631 1,631 Furniture and fixtures 390 390 27,912 25,771 Less: Accumulated depreciation and amortization (11,283) (10,207) $ 16,629 $ 15,564
Schedule of Accrued Liabilities and Other	Accrued Liabilities and Other : March 31, 2023 December 31, 2022 (in thousands) Accrued compensation and related expenses $ 7,487 $ 11,365 Accrued royalty 996 818 Accrued professional services 652 355 Others 761 973 $ 9,896 $ 13,511
Schedule of Accounts Receivable and Allowance for Credit Losses	The movement in the allowance for credit losses was as follows: March 31, 2023 December 31, 2022 (in thousands) Balance at beginning of period $ 400 $ 264 Provision 50 150 Write-offs — (14) Balance at end of period $ 450 $ 400

Commitments and Contingencies (

Commitments and Contingencies (Tables)	3 Months Ended
	Mar. 31, 2023
Commitments and Contingencies Disclosure [Abstract]
Summary of Information Related to Lease Expense and Valuation of Lease Assets and Lease Liabilities	Supplemental information related to lease expense and valuation of the lease assets and lease liabilit ies are as follows: Three Months Ended 2023 2022 Operating lease expense $ 394 $ 409 Variable lease expense 76 104 Total lease expense $ 470 $ 513 Cash paid for amounts included in the measurement of operating lease liabilities $ 398 $ 408 Leased assets obtained in exchange for new operating lease liabilities $ 21 $ — March 31, 2023 December 31, 2022 Weighted average remaining lease term (in years) 2.83 3.05 Weighted average discount rate 5.77% 5.77%
Schedule of Future Minimum Lease Payments Under Non-Cancelable Operating Leases	Future minimum lease payments under non-cancelable operating leases as of March 31, 2023 was as follows: Year Ending December 31, (in thousands) Remainder of 2023 $ 1,195 2024 1,517 2025 1,005 2026 530 2027 9 Thereafter — Total operating lease payments 4,256 Less: imputed interest (330) Total operating lease liabilities $ 3,926

Borrowings (Tables)

Borrowings (Tables)	3 Months Ended
	Mar. 31, 2023
Debt Disclosure [Abstract]
Schedule of Outstanding Borrowings	The following table summarizes the outstanding borrowings from the term loan as of periods presented: March 31, 2023 December 31, 2022 (in thousands) Principal outstanding and final fee $ 36,720 $ 35,700 Less: Unamortized debt issuance costs (99) (73) Unaccreted value of final fee (683) (456) Outstanding debt, net of debt issuance costs and unaccreted value of final fee $ 35,938 $ 35,171 Classified as: Long-term borrowings $ 35,938 $ 35,171
Schedule of Future Principal and Final Fee Payments	The table below summarizes the future principal and final fee payments under the Fist-Citizens Term Loan as of March 31, 2023: Year ending December 31, (in thousands) Remainder of 2023 $ — 2024 — 2025 8,400 2026 14,400 2027 13,920 Total principal and final fee payments $ 36,720

Stock-Based Incentive Compens_2

Stock-Based Incentive Compensation Plans (Tables)	3 Months Ended
	Mar. 31, 2023
Share-Based Payment Arrangement [Abstract]
Schedule of Stock Option Activity	The table below summarizes the stock option activity for the three months ended March 31, 2023: Number of Weighted- Outstanding as of December 31, 2022 1,903,341 $8.82 Exercised (120,266) 4.33 Canceled and forfeited (15,284) 21.36 Outstanding as of March 31, 2023 1,767,791 10.23
Schedule of Share-based Payment Award, Equity Instruments Other Than Options, Valuation Assumptions	The table below summarizes the assumptions used to estimate the grant date fair value of the PSUs granted: Three Months Ended March 31, 2023 2022 Expected volatility of common stock 58.0% to 73.0% 48.9% to 58.7% Expected volatility of peer companies 33.0% to 141.0% 24.2% to 152.5% Correlation coefficient of peer companies (0.15) to 1.00 (0.13) to 1.00 Risk-free interest rate 3.9% to 5.0% 0.4% to 1.2% Dividend yield —% to 1.3% —% to 1.0%
Schedule of Restricted Stock Unit Activity	The table below summarizes RSU and PSU activity for the three months ended March 31, 2023: RSUs PSUs Number of Shares Weighted Average Grant Date Fair Value Number of Shares Weighted Average Grant Date Fair Value Outstanding as of December 31, 2022 1,794,928 $22.72 155,596 $19.50 Granted 1,044,344 15.69 255,458 12.33 Vested (228,388) 22.97 (25,932) 19.50 Canceled and forfeited (86,107) 21.70 — — Outstanding as of March 31, 2023 2,524,777 19.82 385,122 14.74
Schedule of Performance-based Restricted Stock Unit Activity Arrangement	The table below summarizes RSU and PSU activity for the three months ended March 31, 2023: RSUs PSUs Number of Shares Weighted Average Grant Date Fair Value Number of Shares Weighted Average Grant Date Fair Value Outstanding as of December 31, 2022 1,794,928 $22.72 155,596 $19.50 Granted 1,044,344 15.69 255,458 12.33 Vested (228,388) 22.97 (25,932) 19.50 Canceled and forfeited (86,107) 21.70 — — Outstanding as of March 31, 2023 2,524,777 19.82 385,122 14.74
Schedule of Stock-Based Compensation	The table below presents the detail of stock-based compensation expense amounts included in the condensed consolidated statements of operations: Three Months Ended 2023 2022 (in thousands) Cost of goods sold $ 137 $ 123 Sales and marketing 2,910 2,594 Research and development 752 633 General and administrative 2,395 2,157 $ 6,194 $ 5,507

Net Loss Per Share of Common _2

Net Loss Per Share of Common Stock (Tables)	3 Months Ended
	Mar. 31, 2023
Earnings Per Share [Abstract]
Schedule of Computation of Basic and Diluted Net Loss per Share	The table below summarizes the computation of basic and diluted net loss per share: Three Months Ended March 31, 2023 2022 (in thousands, except share and per share data) Net loss $ (11,125) $ (17,410) Weighted-average shares used to compute basic and diluted net loss per share 34,916,106 33,792,326 Net loss per share, basic and diluted $ (0.32) $ (0.52)
Schedule of Anti-dilutive Common Stock Equivalents Excluded from Computation of Diluted Net Loss per Share	The following anti-dilutive common stock equivalents were excluded from the computation of diluted net loss per share for the periods presented: Three Months Ended March 31, 2023 2022 Stock options 1,767,791 1,963,360 Restricted stock units 2,909,899 2,309,284 ESPP purchase rights 134,226 61,264 Common stock warrants 118,122 118,122 4,930,038 4,452,030

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Narrative (Details)	Mar. 31, 2023 activity
Accounting Policies [Abstract]
Number of business activities	1

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Revenue by Geography (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Disaggregation of Revenue [Line Items]
Revenue	$ 32,708	$ 22,439
United States
Disaggregation of Revenue [Line Items]
Revenue	30,450	20,367
International
Disaggregation of Revenue [Line Items]
Revenue	$ 2,258	$ 2,072

Marketable Securities - Schedul

Marketable Securities - Schedule of Marketable Securities (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Cash equivalents
Carrying value	$ 15,602	$ 8,002
Short-term investments
Amortized Cost	63,008	76,674
Unrealized Gains	18	7
Unrealized Losses	(29)	(108)
Aggregate Fair Value	62,997	76,573
Total marketable securities, Amortized Cost	78,610	84,676
Total marketable securities, Aggregate Fair Value	78,599	84,575
Money market funds
Cash equivalents
Carrying value	15,602	8,002
U.S. treasury securities
Short-term investments
Amortized Cost	35,978	48,636
Unrealized Gains	7	4
Unrealized Losses	(21)	(105)
Aggregate Fair Value	35,964	48,535
Corporate bonds
Short-term investments
Amortized Cost	2,945	2,914
Unrealized Gains	0	0
Unrealized Losses	(7)	(3)
Aggregate Fair Value	2,938	2,911
Commercial paper
Short-term investments
Amortized Cost	18,265	22,206
Unrealized Gains	0	0
Unrealized Losses	0	0
Aggregate Fair Value	18,265	22,206
U.S. agency bonds
Short-term investments
Amortized Cost	5,820	2,918
Unrealized Gains	11	3
Unrealized Losses	(1)	0
Aggregate Fair Value	$ 5,830	$ 2,921

Marketable Securities - Narrati

Marketable Securities - Narrative (Details) - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2023	Dec. 31, 2022
Investments, Debt and Equity Securities [Abstract]
Credit losses on investments	$ 0	$ 0
Accrued interest receivable	100,000
Accrued interest writeoff	$ 0	$ 0

Fair Value Measurement (Details

Fair Value Measurement (Details) - Recurring - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Marketable securities
Marketable securities	$ 78,599	$ 84,575
Money market funds
Marketable securities
Marketable securities	15,602	8,002
U.S. treasury securities
Marketable securities
Marketable securities	35,964	48,535
Corporate bonds
Marketable securities
Marketable securities	2,938	2,911
U.S. agency bonds
Marketable securities
Marketable securities	5,830	2,921
Commercial paper
Marketable securities
Marketable securities	18,265	22,206
Level 1
Marketable securities
Marketable securities	51,566	56,537
Level 1 | Money market funds
Marketable securities
Marketable securities	15,602	8,002
Level 1 | U.S. treasury securities
Marketable securities
Marketable securities	35,964	48,535
Level 1 | Corporate bonds
Marketable securities
Marketable securities	0	0
Level 1 | U.S. agency bonds
Marketable securities
Marketable securities	0	0
Level 1 | Commercial paper
Marketable securities
Marketable securities	0	0
Level 2
Marketable securities
Marketable securities	27,033	28,038
Level 2 | Money market funds
Marketable securities
Marketable securities	0	0
Level 2 | U.S. treasury securities
Marketable securities
Marketable securities	0	0
Level 2 | Corporate bonds
Marketable securities
Marketable securities	2,938	2,911
Level 2 | U.S. agency bonds
Marketable securities
Marketable securities	5,830	2,921
Level 2 | Commercial paper
Marketable securities
Marketable securities	18,265	22,206
Level 3
Marketable securities
Marketable securities	0	0
Level 3 | Money market funds
Marketable securities
Marketable securities	0	0
Level 3 | U.S. treasury securities
Marketable securities
Marketable securities	0	0
Level 3 | Corporate bonds
Marketable securities
Marketable securities	0	0
Level 3 | U.S. agency bonds
Marketable securities
Marketable securities	0	0
Level 3 | Commercial paper
Marketable securities
Marketable securities	$ 0	$ 0

Balance Sheet Components - Narr

Balance Sheet Components - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Property, Plant and Equipment [Line Items]
Inventory, finished goods, gross	$ 16,300		$ 15,600
Inventory, work in process, gross	1,500		1,700
Property and equipment, gross	27,912		$ 25,771
Depreciation expense	1,100	$ 700
Construction in progress, surgical placement instrument set
Property, Plant and Equipment [Line Items]
Property and equipment, gross	4,000
Construction in Progress, Santa Clara Lease
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 3,700

Balance Sheet Components - Prop

Balance Sheet Components - Property and Equipment, Net (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Property and Equipment, Net
Property and equipment, gross	$ 27,912	$ 25,771
Less: Accumulated depreciation and amortization	(11,283)	(10,207)
Property and equipment, net	16,629	15,564
Machinery and equipment
Property and Equipment, Net
Property and equipment, gross	17,070	14,920
Construction in progress
Property and Equipment, Net
Property and equipment, gross	7,682	7,854
Computer and office equipment
Property and Equipment, Net
Property and equipment, gross	1,139	976
Leasehold improvements
Property and Equipment, Net
Property and equipment, gross	1,631	1,631
Furniture and fixtures
Property and Equipment, Net
Property and equipment, gross	$ 390	$ 390

Balance Sheet Components - Accr

Balance Sheet Components - Accrued Liabilities and Other (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Accrued Liabilities and Other
Accrued compensation and related expenses	$ 7,487	$ 11,365
Accrued royalty	996	818
Accrued professional services	652	355
Others	761	973
Accrued liabilities and other	$ 9,896	$ 13,511

Balance Sheet Components - Acco

Balance Sheet Components - Accounts Receivable and Allowance for Credit Losses (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	$ 400	$ 264	$ 264
Provision	50	$ 0	150
Write-offs	0		(14)
Balance at end of period	$ 450		$ 400

Commitment and Contingencies -

Commitment and Contingencies - Supplemental Information Related to Lease Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Commitments and Contingencies Disclosure [Abstract]
Operating lease expense	$ 394	$ 409
Variable lease expense	76	104
Total lease expense	470	513
Cash paid for amounts included in the measurement of operating lease liabilities	398	408
Leased assets obtained in exchange for new operating lease liabilities	$ 21	$ 0
Weighted average remaining lease term (in years)	2 years 9 months 29 days		3 years 18 days
Weighted average discount rate	5.77%		5.77%

Commitments and Contingencies -

Commitments and Contingencies - Aggregate Future Minimum Lease Payments (Details) $ in Thousands	Mar. 31, 2023 USD ($)
Aggregate Future Minimum Lease Payments
Remainder of 2023	$ 1,195
2024	1,517
2025	1,005
2026	530
2027	9
Thereafter	0
Total operating lease payments	4,256
Less: imputed interest	(330)
Total operating lease liabilities	$ 3,926

Commitments and Contingencies_2

Commitments and Contingencies - Narrative (Details) - USD ($)	3 Months Ended
	Mar. 31, 2023	Dec. 31, 2022
Other Commitments [Line Items]
Operating lease liabilities that had not commenced.	$ 0
Purchase commitments related to inventory management and training materials	1,800,000	$ 800,000
Indemnification Agreement
Other Commitments [Line Items]
Costs to defend lawsuits or settle claims	0
Liability associated with indemnifications	$ 0

Borrowings - Summary of Borrowi

Borrowings - Summary of Borrowings (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Debt Disclosure [Abstract]
Principal outstanding and final fee	$ 36,720	$ 35,700
Less: Unamortized debt issuance costs	(99)	(73)
Unaccreted value of final fee	(683)	(456)
Outstanding debt, net of debt issuance costs and unaccreted value of final fee	35,938	35,171
Long-term borrowings	$ 35,938	$ 35,171

Borrowings - Narrative (Details

Borrowings - Narrative (Details)		3 Months Ended
	Jan. 06, 2023 USD ($) quick_ratio	Mar. 31, 2023	Mar. 31, 2022	Aug. 12, 2021 USD ($)
SVB Term Loan | Term loan
Debt Instrument [Line Items]
Aggregate principal amount	$ 35,000,000			$ 35,000,000
Proceeds from (Repayments of) Secured Debt	35,000,000
Effective interest rate during the period (percent)		8.60%
Contingent interest rate increase due to default		3%
SVB Amended Term Loan | Term loan
Debt Instrument [Line Items]
Proceeds from (Repayments of) Secured Debt	$ (36,000,000)
Final fee as percentage of aggregate principal amount (percent)	2%
SVB Amended Term Loan | Term loan | Minimum
Debt Instrument [Line Items]
Basis spread on variable rate	0.50%
SVB Amended Term Loan | Term loan | Maximum
Debt Instrument [Line Items]
Basis spread on variable rate	6.75%
SVB Amended Term Loan | Term loan | Revolving Credit Facility
Debt Instrument [Line Items]
Accordion feature, increase limit	$ 15,000,000
Accounts receivable borrowing base (percent)	80%
Fixed interest rate (percent)	6.25%
Adjusted quick ratio threshold | quick_ratio	1.5
SVB Amended Term Loan | Line of Credit | Revolving Credit Facility
Debt Instrument [Line Items]
Revolving credit facility, aggregate principal amount	$ 15,000,000
Total commitment fee, amount	187,500
Contingent fee, amount	$ 150,000
Solar Term Loan | Term loan
Debt Instrument [Line Items]
Effective interest rate during the period (percent)			6.30%

Borrowings - Debt Maturity (Det

Borrowings - Debt Maturity (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Future principal and final fee payments
Remainder of 2023	$ 0
2024	0
2025	8,400
2026	14,400
2027	13,920
Total principal and final fee payments	$ 36,720	$ 35,700

Stock-Based Incentive Compens_3

Stock-Based Incentive Compensation Plans - Stock Option Activity (Details)	3 Months Ended
	Mar. 31, 2023 $ / shares shares
Number of Shares
Outstanding, beginning of period (in shares) | shares	1,903,341
Exercised (in shares) | shares	(120,266)
Canceled and forfeited (in shares) | shares	(15,284)
Outstanding, end of period (in shares) | shares	1,767,791
Weighted-Average Exercise Price
Outstanding, beginning of period (in dollars per share) | $ / shares	$ 8.82
Exercised (in dollars per share) | $ / shares	4.33
Canceled and forfeited (in dollars per share) | $ / shares	21.36
Outstanding, end of period (in dollars per share) | $ / shares	$ 10.23

Stock-Based Incentive Compens_4

Stock-Based Incentive Compensation Plans - Narrative (Details) $ in Millions	1 Months Ended		3 Months Ended
	Jan. 31, 2022	May 31, 2020 purchase_period	Mar. 31, 2023 USD ($) shares	Mar. 31, 2022 shares	Dec. 31, 2022 USD ($) shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options granted (in shares) | shares			0	0
Early exercise of stock options, share subject to repurchase (in shares) | shares			0		0
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost, expected period for recognition (in years)			4 months 24 days
Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost, expected period for recognition (in years)			2 years 9 months 18 days
Unrecognized compensation cost			$ 41.5
Restricted Stock Units | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance period			2 years
Restricted Stock Units | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance period			4 years
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost, expected period for recognition (in years)			2 years 4 months 24 days
Unrecognized compensation cost			$ 4.1
2018 ESPP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Purchase price of common stock as a percent of fair market value (percent)			85%
Employee stock purchase program offering period interval (in months)		12 months	6 months
Number of purchase periods in offering interval | purchase_period		2
Accrued compensation and related expenses for employee payroll deductions			$ 1.2		$ 0.3
2018 ESPP | Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance period	3 years

Stock-Based Incentive Compens_5

Stock-Based Incentive Compensation Plans - Valuation Assumptions for Stock Options (Details) - Performance Shares	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Black-Scholes option-pricing model assumptions
Expected volatility of common stock, minimum (percent)	58%	48.90%
Expected volatility of common stock, maximum (percent)	73%	58.70%
Expected volatility of peer companies, minimum (percent)	33%	24.20%
Expected volatility of peer companies, maximum (percent)	141%	152.50%
Correlation coefficient of peer companies, minimum	(15.00%)	(13.00%)
Correlation coefficient of peer companies, maximum	100%	100%
Risk-free interest rate, minimum (percent)	3.90%	0.40%
Risk-free interest rate, maximum (percent)	5%	1.20%
Minimum
Black-Scholes option-pricing model assumptions
Dividend yield (percent)	0%	0%
Maximum
Black-Scholes option-pricing model assumptions
Dividend yield (percent)	1.30%	1%

Stock-Based Incentive Compens_6

Stock-Based Incentive Compensation Plans - Restricted Stock Units Activity and Performance-Based Restricted Stock Unit Activity (Details)	3 Months Ended
	Mar. 31, 2023 $ / shares shares
Restricted Stock Units
Number of Shares
Outstanding, beginning of period (in shares) | shares	1,794,928
Granted (in shares) | shares	1,044,344
Vested (in shares) | shares	(228,388)
Canceled and forfeited (in shares) | shares	(86,107)
Outstanding, end of period (in shares) | shares	2,524,777
Weighted Average Grant Date Fair Value
Outstanding, beginning of period (in dollars per share) | $ / shares	$ 22.72
Granted (in dollars per share) | $ / shares	15.69
Vested (in dollars per share) | $ / shares	22.97
Canceled and forfeited (in dollars per share) | $ / shares	21.70
Outstanding, end of period (in dollars per share) | $ / shares	$ 19.82
Performance Shares
Number of Shares
Outstanding, beginning of period (in shares) | shares	155,596
Granted (in shares) | shares	255,458
Vested (in shares) | shares	(25,932)
Canceled and forfeited (in shares) | shares	0
Outstanding, end of period (in shares) | shares	385,122
Weighted Average Grant Date Fair Value
Outstanding, beginning of period (in dollars per share) | $ / shares	$ 19.50
Granted (in dollars per share) | $ / shares	12.33
Vested (in dollars per share) | $ / shares	19.50
Canceled and forfeited (in dollars per share) | $ / shares	0
Outstanding, end of period (in dollars per share) | $ / shares	$ 14.74

Stock-Based Incentive Compens_7

Stock-Based Incentive Compensation Plans - Stock-Based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 6,194	$ 5,507
Cost of goods sold
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	137	123
Sales and marketing
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	2,910	2,594
Research and development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	752	633
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 2,395	$ 2,157

Net Loss Per Share of Common _3

Net Loss Per Share of Common Stock - Computation of Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Earnings Per Share [Abstract]
Net loss	$ (11,125)	$ (17,410)
Weighted-average number of common shares used to compute basic net loss per share (in shares)	34,916,106	33,792,326
Weighted-average number of common shares used to compute diluted net loss per share (in shares)	34,916,106	33,792,326
Net loss per share, basic (in usd per share)	$ (0.32)	$ (0.52)
Net loss per share, diluted (in usd per share)	$ (0.32)	$ (0.52)

Net Loss Per Share of Common _4

Net Loss Per Share of Common Stock - Antidilutive Common Stock Equivalents Excluded from Computation of Earnings Per Share (Details) - shares	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Common stock equivalents excluded from computation of diluted net loss per share (in shares)	4,930,038	4,452,030
Stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Common stock equivalents excluded from computation of diluted net loss per share (in shares)	1,767,791	1,963,360
Restricted stock units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Common stock equivalents excluded from computation of diluted net loss per share (in shares)	2,909,899	2,309,284
ESPP purchase rights
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Common stock equivalents excluded from computation of diluted net loss per share (in shares)	134,226	61,264
Common stock warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Common stock equivalents excluded from computation of diluted net loss per share (in shares)	118,122	118,122

Related Party Transaction (Deta

Related Party Transaction (Details) - SeaSpine - Joint development agreement - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Related Party Transaction [Line Items]
Reimbursement charges expensed		$ 6
Term of product royalty sales period (in years)	10 years
Royalties		$ 0
Outstanding liability to SeaSpine	$ 60		$ 100

Income Taxes (Details)

Income Taxes (Details) - USD ($)	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Income Tax Disclosure [Abstract]
Income tax provision	$ 0	$ 0