Liquidity and Going Concern Uncertainty	9 Months Ended
Sep. 30, 2018
Accounting Policies [Abstract]
Liquidity and Going Concern Uncertainty	2. Liquidity and Going Concern Uncertainty As of September 30, 2018, cash totaled $9.0 million and the Company had an accumulated deficit of $214.4 million. For the nine months ended September 30, 2018, the Company incurred a net loss of $18.6 million. At September 30, 2018, the Company had aggregate net interest-bearing indebtedness of $1.7 million, of which $693,000 was due within one year whereas at September 30, 2017, the Company had aggregate net interest-bearing indebtedness of $3.3 million, of which $2.4 million was due within one year in the absence of subjective acceleration of amounts due under a credit facility entered into in April 2014 with Oxford Finance LLC, or the April 2014 Credit Facility. Additionally, in February 2016, the Company signed a firm, non-cancelable, and unconditional commitment in an aggregate amount of $1,062,500 with a vendor to purchase certain inventory items, payable in minimum quarterly amounts of $62,500 through May 2020, under which $404,000 remained outstanding at September 30, 2018 (see Note 11). These factors raise substantial doubt about the Company’s ability to continue as a going concern for the one-year period following the date that these financial statements were issued. The accompanying financial statements and notes have been prepared assuming that the Company will continue as a going concern. The accompanying financial statements and notes do not include any adjustments to reflect the possible future effects on the recoverability and classification of assets or the amounts and classification of liabilities that may result from the possible inability of the Company to continue as a going concern. While the Company is currently in the commercialization stage of operations, the Company has not yet achieved profitability and anticipates that it will continue to incur net losses for the foreseeable future. Historically, the Company’s principal sources of cash have included proceeds from the issuance of common and preferred stock, proceeds from the exercise of warrants to purchase common stock, proceeds from the issuance of debt, and revenues from laboratory services. The Company’s principal uses of cash have included cash used in operations, payments relating to purchases of property and equipment and repayments of borrowings. The Company expects that the principal uses of cash in the future will be for continuing operations, hiring of sales and marketing personnel and increased sales and marketing activities, funding of research and development, capital expenditures, and general working capital requirements. The Company expects that, as revenues grow, sales and marketing and research and development expenses will continue to grow, albeit at a slower rate and, as a result, the Company will need to generate significant growth in net revenues to achieve and sustain income from operations. On September 20, 2018, the Company completed an offering of 642,438 shares of the Company’s common stock and pre-funded warrants to purchase up to an aggregate of 120,000 shares of its common stock. The shares were sold at a purchase price of $3.285 per share and the pre-funded warrants were sold at a purchase price of $3.275 per pre-funded warrant which represents the per share purchase price for the shares less the $0.01 per share exercise price for each such pre-funded warrant. The net proceeds to the Company from the offering were approximately $2.2 million, after deducting expenses related to the offering including dealer-manager fees and expenses, and excluding any proceeds received upon exercise of any warrants. In addition, in a concurrent private placement, the Company issued to purchasers a warrant to purchase one share of the Company’s common stock for each share and pre-funded warrant purchased for cash in the offering. All warrants issued in this offering have an exercise price of $3.16 per share, are exercisable upon the six-month anniversary of issuance and expire five years from such date. On August 13, 2018, the Company completed a rights offering pursuant to an effective registration statement. Pursuant to the rights offering, the Company sold an aggregate of 11,587 units consisting of an aggregate of 11,587 shares of Series A Preferred Stock and 2,549,140 warrants, with each warrant exercisable for one share of its common stock at an exercise price of $4.53 per share, resulting in net proceeds to the Company of approximately $10.2 million, after deducting expenses relating to the rights offering, including dealer-manager fees and expenses, and excluding any proceeds received upon exercise of any warrants. In May 2018, the SEC declared effective a shelf registration statement filed by the Company, which expires in May 2021. The shelf registration statement allows the Company to issue any combination of its common stock, preferred stock, debt securities and warrants from time to time for an aggregate initial offering price of up to $50 million, subject to certain limitations for so long as its public float is less than $75 million. On January 30, 2018, the Company received net cash proceeds of approximately $13.3 million from the closing of a follow-on public offering of 1,095,153 shares of its common stock and warrants to purchase up to an aggregate of 1,095,153 shares of its common stock at a combined offering price of $13.50 per unit. Subsequent to the closing of this offering, no additional cash proceeds have been received from the exercise of warrants sold in this offering, with approximately $16.4 million in gross warrant proceeds remaining outstanding and available to be exercised at $4.53 per share, which is subject to down round adjustment, until their expiration in January 2023. Pursuant to a common stock and warrant purchase agreement dated August 9, 2017 between the Company and Ally Bridge LB Healthcare Master Fund Limited, or Ally Bridge, the Company received net cash proceeds of approximately $2.0 million from the sale of its common stock and warrants. Subsequent to the closing of this offering, no additional cash proceeds had been received from the exercise of warrants sold in this offering, with approximately $2.2 million in gross warrant proceeds remaining outstanding and available to be exercised at $45.00 per share until their expiration in August 2022. Management’s Plan to Continue as a Going Concern In order to continue as a going concern, the Company will need, among other things, additional capital resources. Until the Company can generate significant cash from operations, including assay revenues, management’s plans to obtain such resources for the Company include proceeds from offerings of the Company’s equity securities or debt, cash received from the exercise of outstanding common stock warrants, or transactions involving product development, technology licensing or collaboration. Management can provide no assurances that any sources of a sufficient amount of financing will be available to the Company on favorable terms, if at all.

2. Liquidity and Going Concern Uncertainty

As of September 30, 2018, cash totaled $9.0 million and the Company had an accumulated deficit of $214.4 million. For the nine months ended September 30, 2018, the Company incurred a net loss of $18.6 million. At September 30, 2018, the Company had aggregate net interest-bearing indebtedness of $1.7 million, of which $693,000 was due within one year whereas at September 30, 2017, the Company had aggregate net interest-bearing indebtedness of $3.3 million, of which $2.4 million was due within one year in the absence of subjective acceleration of amounts due under a credit facility entered into in April 2014 with Oxford Finance LLC, or the April 2014 Credit Facility. Additionally, in February 2016, the Company signed a firm, non-cancelable, and unconditional commitment in an aggregate amount of $1,062,500 with a vendor to purchase certain inventory items, payable in minimum quarterly amounts of $62,500 through May 2020, under which $404,000 remained outstanding at September 30, 2018 (see Note 11). These factors raise substantial doubt about the Company’s ability to continue as a going concern for the one-year period following the date that these financial statements were issued. The accompanying financial statements and notes have been prepared assuming that the Company will continue as a going concern. The accompanying financial statements and notes do not include any adjustments to reflect the possible future effects on the recoverability and classification of assets or the amounts and classification of liabilities that may result from the possible inability of the Company to continue as a going concern.

While the Company is currently in the commercialization stage of operations, the Company has not yet achieved profitability and anticipates that it will continue to incur net losses for the foreseeable future. Historically, the Company’s principal sources of cash have included proceeds from the issuance of common and preferred stock, proceeds from the exercise of warrants to purchase common stock, proceeds from the issuance of debt, and revenues from laboratory services. The Company’s principal uses of cash have included cash used in operations, payments relating to purchases of property and equipment and repayments of borrowings. The Company expects that the principal uses of cash in the future will be for continuing operations, hiring of sales and marketing personnel and increased sales and marketing activities, funding of research and development, capital expenditures, and general working capital requirements. The Company expects that, as revenues grow, sales and marketing and research and development expenses will continue to grow, albeit at a slower rate and, as a result, the Company will need to generate significant growth in net revenues to achieve and sustain income from operations.

On September 20, 2018, the Company completed an offering of 642,438 shares of the Company’s common stock and pre-funded warrants to purchase up to an aggregate of 120,000 shares of its common stock. The shares were sold at a purchase price of $3.285 per share and the pre-funded warrants were sold at a purchase price of $3.275 per pre-funded warrant which represents the per share purchase price for the shares less the $0.01 per share exercise price for each such pre-funded warrant. The net proceeds to the Company from the offering were approximately $2.2 million, after deducting expenses related to the offering including dealer-manager fees and expenses, and excluding any proceeds received upon exercise of any warrants. In addition, in a concurrent private placement, the Company issued to purchasers a warrant to purchase one share of the Company’s common stock for each share and pre-funded warrant purchased for cash in the offering. All warrants issued in this offering have an exercise price of $3.16 per share, are exercisable upon the six-month anniversary of issuance and expire five years from such date.

On August 13, 2018, the Company completed a rights offering pursuant to an effective registration statement. Pursuant to the rights offering, the Company sold an aggregate of 11,587 units consisting of an aggregate of 11,587 shares of Series A Preferred Stock and 2,549,140 warrants, with each warrant exercisable for one share of its common stock at an exercise price of $4.53 per share, resulting in net proceeds to the Company of approximately $10.2 million, after deducting expenses relating to the rights offering, including dealer-manager fees and expenses, and excluding any proceeds received upon exercise of any warrants.

In May 2018, the SEC declared effective a shelf registration statement filed by the Company, which expires in May 2021. The shelf registration statement allows the Company to issue any combination of its common stock, preferred stock, debt securities and warrants from time to time for an aggregate initial offering price of up to $50 million, subject to certain limitations for so long as its public float is less than $75 million.

On January 30, 2018, the Company received net cash proceeds of approximately $13.3 million from the closing of a follow-on public offering of 1,095,153 shares of its common stock and warrants to purchase up to an aggregate of 1,095,153 shares of its common stock at a combined offering price of $13.50 per unit. Subsequent to the closing of this offering, no additional cash proceeds have been received from the exercise of warrants sold in this offering, with approximately $16.4 million in gross warrant proceeds remaining outstanding and available to be exercised at $4.53 per share, which is subject to down round adjustment, until their expiration in January 2023.

Pursuant to a common stock and warrant purchase agreement dated August 9, 2017 between the Company and Ally Bridge LB Healthcare Master Fund Limited, or Ally Bridge, the Company received net cash proceeds of approximately $2.0 million from the sale of its common stock and warrants. Subsequent to the closing of this offering, no additional cash proceeds had been received from the exercise of warrants sold in this offering, with approximately $2.2 million in gross warrant proceeds remaining outstanding and available to be exercised at $45.00 per share until their expiration in August 2022.

Management’s Plan to Continue as a Going Concern

In order to continue as a going concern, the Company will need, among other things, additional capital resources. Until the Company can generate significant cash from operations, including assay revenues, management’s plans to obtain such resources for the Company include proceeds from offerings of the Company’s equity securities or debt, cash received from the exercise of outstanding common stock warrants, or transactions involving product development, technology licensing or collaboration. Management can provide no assurances that any sources of a sufficient amount of financing will be available to the Company on favorable terms, if at all.