Basis of Presentation and Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2013
Description of Business and Basis of Presentation	Description of Business and Basis of Presentation Corcept Therapeutics Incorporated was incorporated in the state of Delaware in May 1998, and our facilities are located in Menlo Park, California. Corcept is a pharmaceutical company engaged in the discovery, development and commercialization of drugs for the treatment of severe metabolic and psychiatric disorders. Since our inception, we have been developing our lead product, Korlym^®. Mifepristone, the active ingredient in Korlym, is a potent competitive antagonist of the glucocorticoid receptor II (GR-II), which means that it competitively blocks the effects of cortisol throughout the body at one of its two receptors. In February 2012, the United States Food and Drug Administration (FDA) approved Korlym (mifepristone) 300 mg Tablets in the United States as a once-daily oral medication for treatment of hyperglycemia secondary to hypercortisolism in adult patients with endogenous Cushing’s syndrome who have type 2 diabetes mellitus or glucose intolerance and have failed surgery or are not candidates for surgery. We released Korlym for sale in April 2012. We also have a clinical program for the use of mifepristone for the treatment of the psychotic features of psychotic depression. We are currently conducting a phase 3 study for this indication. In addition, we have discovered and patented three series of novel selective glucocorticoid receptor II (GR-II) antagonists. Unless otherwise stated, all references in these financial statements to “we,” “us,” “our,” “Corcept,” the “Company,” “our company” and similar designations refer to Corcept Therapeutics Incorporated. The accompanying unaudited condensed balance sheet as of June 30, 2013 and the condensed statements of comprehensive loss and condensed statements of cash flows for the three- and six-month periods ended June 30, 2013 and 2012 have been prepared in accordance with U.S. generally accepted accounting principles for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by U.S. generally accepted accounting principles for complete financial statements. In the opinion of management, all adjustments (consisting only of normal recurring adjustments) considered necessary for a fair presentation have been included. Operating results for the three- and six-month periods ended June 30, 2013 are not necessarily indicative of the results that may be expected for the year ending December 31, 2013 or any other period. These financial statements and notes should be read in conjunction with the financial statements for the year ended December 31, 2012 included in our Annual Report on Form 10-K. The accompanying balance sheet as of December 31, 2012 has been derived from audited financial statements at that date.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with U.S. generally accepted accounting principles requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Actual results could differ materially from those estimates. We evaluate our estimates and assumptions on an ongoing basis, including those related to our discounts for prompt payment of sales invoices, chargebacks and rebates, patient assistance, potential product returns, excess/obsolete inventories, allowances for doubtful accounts, accruals of clinical and preclinical expenses, contingent liabilities, and the timing of payments with respect to our long-term capped royalty obligation, which determine its effective interest rate. We base our estimates on relevant experience and on other specific assumptions that we believe are reasonable. We update our assumptions and estimates on a recurring basis as new information becomes available. Any changes in estimates are recorded in the period of the change.
Cash and Cash Equivalents	Cash and Cash Equivalents We invest our cash in bank deposits, money market accounts, corporate debt securities and obligations of the U.S. government and U.S. government sponsored entities. We consider all highly liquid investments purchased with maturities of three months or less from the date of purchase to be cash equivalents. Cash equivalents are carried at fair value, which approximates cost. As of June 30, 2013 and December 31, 2012, all of our funds were invested in cash and cash equivalents that consist of a money market fund maintained at a major U.S. financial institution.
Credit Risks and Concentrations	Credit Risks and Concentrations We have a concentration of credit risk related to our cash and cash equivalents. We are exposed to credit risk in the event of default by the financial institutions holding these funds to the extent of the amount recorded on our balance sheet. We mitigate this risk by investing in a money market fund that invests primarily in short-term U.S. Treasury notes and bills. We experienced no loss or lack of access to cash and cash equivalents in our operating or investment accounts during the three- and six-month periods ended June 30, 2013 and 2012. Since the commercialization of Korlym in April 2012, we have been exposed to credit risk in regard to our trade receivables. From the launch of Korlym through June 30, 2013, approximately 97% of our sales were to one specialty pharmacy customer, from whom we have fully collected all receivables. As discussed in Note 5, *Significant Agreements – Specialty Pharmacy for Korlym*, we have transitioned all of our specialty pharmacy business to a new provider, Centric Health Resources, Inc. (Centric). Among other services, Centric will dispense Korlym to patients for us, with title to the medicine passing from us to the patient upon patient’s receipt of the drug. Accordingly, our receivables risk will be spread among various third-party payors – pharmacy benefit managers, insurance companies and government programs – and individual patients. We extend credit to third-party payors based on their creditworthiness. We monitor our exposure and will record a reserve against uncollectible trade receivables as necessary. We also have a concentration of risk in regard to the manufacture of our product. As of June 30, 2013, we had one tablet manufacturer for Korlym with an operational facility, AAI Pharma (AAI), which was approved by the FDA in November 2012 for the manufacture of our commercial tablets. We are currently in negotiations for a commercial manufacturing agreement with AAI Pharma. Our original tablet manufacturer, PharmaForm, which has been acquired by Formex LLC (Formex), has temporarily suspended manufacturing operations to relocate to a new facility for which it will need to obtain FDA approval. If Formex is not able to qualify their new site or if AAI Pharma is unable to prepare Korlym tablets in the quantities and time frame required, we may not be able to manufacture our product in a timely manner. In addition, we have a single-source manufacturer of mifepristone, the active pharmaceutical ingredient (API), in Korlym. In order to mitigate these risks related to the manufacture of our product, we placed strategic orders for additional quantities of mifepristone API during 2012 and had our original tablet manufacturer, Formex, prepare additional batches during the summer of 2012 before the closure of their qualified manufacturing site.
Fair Value Measurements	Fair Value Measurements We categorize financial instruments in a fair value hierarchy that prioritizes the information used to develop assumptions for measuring fair value. The fair value hierarchy gives the highest priority to quoted prices in active markets for identical assets or liabilities (Level 1 input), then to quoted prices (in non-active markets or in active markets for similar assets or liabilities), inputs other than quoted prices that are observable for the asset or liability, and inputs that are not directly observable, but that are corroborated by observable market data for the asset or liability (Level 2 input), then the lowest priority to unobservable inputs, for example, our own data about the assumptions that market participants would use in pricing an asset or liability (Level 3 input). Fair value is a market-based measurement, not an entity-specific measurement, and a fair value measurement should therefore be based on the assumptions that market participants would use in pricing the asset or liability. No assets or liabilities in our financial statements are required to be reported at fair value other than our cash equivalents.
Trade Receivables, net	Trade Receivables, net Trade receivables are recorded net of customer allowances for prompt payment and data services, doubtful accounts and sales returns. See the discussion below under “Net Product Sales” regarding the methods for estimation of these allowances and sales returns. We determine our allowance for doubtful accounts based on existing contractual payment terms, actual payment patterns of our customers and individual customer circumstances. To date, we have determined that an allowance for uncollectible trade receivables is not required.
Inventory	Inventory We consider regulatory approval of product candidates to be uncertain, and product manufactured prior to regulatory approval may not be sold unless regulatory approval is obtained. We expense the manufacturing costs for product candidates incurred prior to regulatory approval as research and development expense as we incur them. When regulatory approval of a product is obtained, we begin capitalizing manufacturing costs related to the approved product into inventory, provided such product is produced by a facility the FDA has approved to manufacture Korlym. We value our inventories at the lower of cost or net realizable value. We determine the cost of inventory using the specific identification method, which approximates a first-in, first-out basis. We analyze our inventory levels quarterly and write down inventory that has become obsolete or has a cost basis in excess of its expected net realizable value, as well as any inventory quantities in excess of expected requirements. Any expired inventory is disposed of and the related costs are recognized as cost of sales in the statement of comprehensive loss. Inventory amounts that are not expected to be consumed within twelve months following the balance sheet date are classified as strategic inventory, a noncurrent asset.
Property and Equipment	Property and Equipment We state property and equipment at cost less accumulated depreciation. Property and equipment are depreciated using the straight-line method over the estimated useful lives of the assets, ranging from three to five years.
Long-term Obligation	Long-term Obligation In August 2012, we entered into a Purchase and Sale Agreement (Financing Agreement) with Biopharma Secured Debt Fund II Sub, S.à r.l (Biopharma), a private limited liability company organized under the laws of Luxembourg. Under the terms of the Financing Agreement, we received $30.0 million from Biopharma and are obligated to make payments calculated as a percentage of (i) any licensing or other contingent payments arising from Korlym and any other products containing mifepristone or any of our proprietary selective GR-II antagonists (Covered Products) and (ii) net Covered Product revenues earned in the calendar quarter ending June 30, 2013 and thereafter (together, Korlym Receipts), until such time as we have paid Biopharma a total of $45.0 million. The accounting for the Financing Agreement requires us to make certain estimates and assumptions, including the timing of royalty payments due to Biopharma, the expected rate of return to Biopharma, the split between current and long-term portions of the obligation and the accretion of related interest expense. Korlym has only been marketed since April 2012 and the magnitude and timing of Korlym revenue is difficult to predict. Therefore, these estimates and assumptions are subject to significant variability and are likely to change as we gain experience marketing Korlym, which will result in changes in our classification of the current and long term portions of the amounts payable pursuant to the Financing Agreement, as well as the internal rate of return paid to Biopharma and the accretion of interest expense related to this obligation. Actual payment amounts will be based on Korlym Receipts over the term of the Financing Agreement but in no event will the total amount paid to Biopharma exceed $45.0 million. The amount shown as the current portion of the obligation is an estimate of the total amount under the Financing Agreement that would be paid to Biopharma within twelve months following June 30, 2013. Under the Financing Agreement, our first payment to Biopharma was not due until July 2013. See Note 4, *Long-term Obligation*, for additional information regarding this agreement.
Net Product Sales	Net Product Sales From its initial launch in April 2012 through June 30, 2013, we have been selling Korlym to a specialty pharmacy and a specialty distributor, which subsequently resell Korlym to patients and healthcare providers. Korlym is not available in retail pharmacies. As discussed in Note 5, *Significant Agreements – Specialty Pharmacy for Korlym, Centric, the specialty pharmacy we began using July 1, 2013, operates on a consignment basis, without carrying any Korlym inventory. Accordingly, all of our sales through Centric will be made directly to patients. We recognize product revenues from sales of Korlym upon delivery to our customers as long as (i) there is persuasive evidence that an arrangement exists between ourselves and the customer, (ii) collectability is reasonably assured and (iii) the price is fixed or determinable. In order to conclude that the price is fixed or determinable, we must be able to (i) calculate gross product revenues from the sales to our customers and (ii) reasonably estimate net product revenues. We calculate gross product revenues based on the price that we charge our customers. We estimate our net product revenues by deducting from our gross product revenues (a) trade allowances, such as discounts for prompt payment and distributor fees, (b) estimated government rebates and chargebacks, (c) reserves for expected product returns and (d) estimated costs of our patient assistance program. We initially record estimates for these deductions at the time we recognize the gross revenue. We update our estimates on a recurring basis as new information becomes available. Trade Allowances:* Through June 30, 2013, we have offered our specialty pharmacy and specialty distributor customers a discount on Korlym sales for payment within 30 days. We also offered them a small discount for the provision of data services. We expected these customers to earn these discounts and, accordingly, deducted them in full from gross product revenues and trade receivables at the time we recognized such revenues. Because of our change in specialty pharmacies, we no longer offer a prompt-payment discount. Rebates and Chargebacks: We contract with Medicaid and other government programs so that Korlym will be eligible for purchase by, or qualify for partial or full reimbursement from, such government programs. We estimate the rebates and chargebacks that we are obligated to provide to government programs and deduct these estimated amounts from our gross product sales at the time the revenues are recognized. We base our estimates of these rebates and chargebacks upon (i) the discount amounts applicable to government-funded programs and (ii) information obtained from our vendors regarding the percentage of sales by our customers to patients who are covered by entities or programs that are eligible for such rebates and chargebacks. Allowances for Patient Assistance Program: We provide financial assistance to eligible patients whose insurance policies require them to pay high deductibles and co-pays. We estimate the cost of assistance to be provided under this program by applying our actual experience regarding such assistance to our estimate of the percentage of our sales in the period that will be provided to patients covered by the program. Sales Returns: Our specialty pharmacy and specialty distribution customers have had the right to return Korlym beginning six months before the labeled expiration date and ending 12 months after the labeled expiration date. This right of return is extended to our specialty distributor channel’s hospital customers who, generally, have the right to return only unopened bottles. Individual patients do not have the right to return product. We have the right to resell returned product, provided the bottles have not been opened or damaged and the product has not expired. The expiration date for the Korlym product sold to date will not occur until May 2014. We estimate the amount of Korlym that we believe will be returned and deduct that estimated amount from gross revenue at the time we recognize such revenue. When estimating future returns, we analyze quantitative and qualitative information including, but not limited to, actual return rates, the amount of product in the distribution channel, the expected shelf life of such product, current and projected product demand, the introduction of competing products that may erode demand, and broad economic and industry-wide indicators. If we cannot reasonably estimate product returns with respect to a particular sale, we defer recognition of revenue from that sale until we can make a reasonable estimate.
Cost of Sales	Cost of Sales Cost of sales includes the cost of product (the cost to manufacture Korlym, which includes material, third-party manufacturing costs and indirect personnel and other overhead costs) based on units for which revenue is recognized in the current period, as well as costs of stability testing, logistics and distribution of the product. We began capitalizing Korlym production costs as inventory following approval by the FDA in February 2012. Prior to receiving FDA approval for Korlym, we expensed all costs related to the manufacturing of the product as incurred; we classified these costs as research and development expense. A portion of the product manufactured prior to FDA approval is available for us to use commercially.
Research and Development	Research and Development Research and development expenses consist of costs incurred for research and development activities that we sponsor. These costs include direct expenses, such as the cost of clinical trials, pre-clinical studies, manufacturing development, preparations for submissions to the FDA and efforts to prosecute and defend those submissions and the development of second-generation compounds, as well as research and development-related overhead expenses. We also expense as incurred nonrefundable payments to third parties and our cost of acquiring technologies and materials used in research and development that have no alternative future use. We base our cost accruals for clinical trials, research and preclinical activities on estimates of work completed under service agreements, milestones achieved, patient enrollment and past experience with similar contracts. Our estimates of work completed and associated cost accruals include our assessments of information from third-party contract research organizations and the overall status of clinical trial and other development and administrative activities.
Segment Reporting	Segment Reporting We determine our operating segments based on the way we organize our business to make operating decisions and assess performance. We have only one operating segment, which concerns the discovery, development and commercialization of pharmaceutical products.
Stock-Based Compensation	Stock-Based Compensation Stock-based compensation for employee and director options We account for stock-based compensation related to option grants to employees and directors under the fair value method, based on the fair value-based measurement of the award at the grant date as determined utilizing the Black-Scholes option valuation model. For service-based awards, we recognize expense over the requisite service period. For options with performance-based vesting criteria, we begin to recognize expense when we believe there is a high degree of probability (i.e., greater than 70%) of achieving the vesting criteria. Stock-based compensation expense related to non-employees We recognize the expense of options granted to non-employees based on the fair-value based measurement of the option grants at the time of vesting. For service-based awards, we recognize expense over the requisite service period. For options with performance-based vesting criteria, we recognize expense based on the minimum number of shares that will vest over time as the criteria are met based on the Black-Scholes valuation of the vested shares.