Liquidity and Going Concern Uncertainty	3 Months Ended
Mar. 31, 2019
Accounting Policies [Abstract]
Liquidity and Going Concern Uncertainty	2. Liquidity and Going Concern Uncertainty As of March 31, 2019, cash totaled $14.8 million and the Company had an accumulated deficit of $226.5 million. For the year ended December 31, 2018 and the three months ended March 31, 2019, the Company incurred net losses of $24.6 million and $5.9 million, respectively. At March 31, 2019, the Company had aggregate net interest-bearing indebtedness of $1.6 million, of which $640,000 was due within one year, in addition to $4.4 million of other non-interest bearing current liabilities. 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 approximately $278,000 remained outstanding at March 31, 2019 (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 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 $1.3 million in gross warrant proceeds remaining outstanding and available to be exercised at $1.20 per share, subject to down round adjustment, until their expiration in January 2023. Pursuant to the down round adjustment feature of the January 2018 warrants, the exercise price of these warrants was adjusted to the $1.20 offering price per share in the February 2019 financing transaction. On May 24, 2018, the SEC declared effective a shelf registration statement filed by us, which expires in May 2021. The shelf registration statement allows us to issue any combination of our 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 our public float is less than $75 million. 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 $10.1 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. 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 initially had 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 January 18, 2019, the Company completed an offering of 990,000 shares of the Company’s common stock. The shares were sold at a purchase price of $2.25 per share and the net proceeds to the Company from this offering were approximately $2.0 million, after deducting expenses related to the offering including dealer-manager fees and expenses. On February 12, 2019, the Company received net cash proceeds of approximately $6.6 million from the closing of a follow-on public offering of 6,250,000 shares of its common stock and warrants to purchase up to an aggregate of 6,250,000 shares of its common stock at a combined offering price of $1.20 per unit. In addition, the Company sold warrants to purchase up to an aggregate of 937,500 shares of the Company’s common stock in connection with the partial exercise of the over-allotment option granted to the underwriters. Upon closing of the transaction, warrants to purchase 915,000 shares were issued pursuant to the placement agents’ partial exercise of their overallotment. Subsequent to the closing of this offering, no additional cash proceeds have been received from the exercise of warrants sold in this offering. On March 11, 2019, the underwriters exercised their overallotment option for 538,867 shares of the Company’s common stock related to the February 12, 2019 follow-on offering, purchasing shares at $1.20 per share for net cash proceeds of approximately $592,000. On March 19, 2019, the Company received net cash proceeds of approximately $7.5 million as a result of completing a registered direct offering of 5,950,000 shares at a negotiated purchase price of $1.37 per share. 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.

Liquidity and Going Concern Uncertainty

3 Months Ended

Mar. 31, 2019

2. Liquidity and Going Concern Uncertainty

As of March 31, 2019, cash totaled $14.8 million and the Company had an accumulated deficit of $226.5 million. For the year ended December 31, 2018 and the three months ended March 31, 2019, the Company incurred net losses of $24.6 million and $5.9 million, respectively. At March 31, 2019, the Company had aggregate net interest-bearing indebtedness of $1.6 million, of which $640,000 was due within one year, in addition to $4.4 million of other non-interest bearing current liabilities. 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 approximately $278,000 remained outstanding at March 31, 2019 (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 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 $1.3 million in gross warrant proceeds remaining outstanding and available to be exercised at $1.20 per share, subject to down round adjustment, until their expiration in January 2023. Pursuant to the down round adjustment feature of the January 2018 warrants, the exercise price of these warrants was adjusted to the $1.20 offering price per share in the February 2019 financing transaction.

On May 24, 2018, the SEC declared effective a shelf registration statement filed by us, which expires in May 2021. The shelf registration statement allows us to issue any combination of our 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 our public float is less than $75 million.

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 $10.1 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.

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 initially had 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 January 18, 2019, the Company completed an offering of 990,000 shares of the Company’s common stock. The shares were sold at a purchase price of $2.25 per share and the net proceeds to the Company from this offering were approximately $2.0 million, after deducting expenses related to the offering including dealer-manager fees and expenses.

On February 12, 2019, the Company received net cash proceeds of approximately $6.6 million from the closing of a follow-on public offering of 6,250,000 shares of its common stock and warrants to purchase up to an aggregate of 6,250,000 shares of its common stock at a combined offering price of $1.20 per unit. In addition, the Company sold warrants to purchase up to an aggregate of 937,500 shares of the Company’s common stock in connection with the partial exercise of the over-allotment option granted to the underwriters. Upon closing of the transaction, warrants to purchase 915,000 shares were issued pursuant to the placement agents’ partial exercise of their overallotment. Subsequent to the closing of this offering, no additional cash proceeds have been received from the exercise of warrants sold in this offering. On March 11, 2019, the underwriters exercised their overallotment option for 538,867 shares of the Company’s common stock related to the February 12, 2019 follow-on offering, purchasing shares at $1.20 per share for net cash proceeds of approximately $592,000.

On March 19, 2019, the Company received net cash proceeds of approximately $7.5 million as a result of completing a registered direct offering of 5,950,000 shares at a negotiated purchase price of $1.37 per share.

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.