The number of warrants issued during the period.

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Cash includes currency on hand as well as demand deposits with banks or financial institutions. It also includes other kinds of accounts that have the general characteristics of demand deposits in that the customer may deposit additional funds at any time and effectively may withdraw funds at any time without prior notice or penalty. Cash equivalents, excluding items classified as marketable securities, include short-term, highly liquid Investments that are both readily convertible to known amounts of cash, and so near their maturity that they present minimal risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify under that definition. Original maturity means original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three years ago does not become a cash equivalent when its remaining maturity is three months. Short-term investments, exclusive of cash equivalents, generally consist of marketable securities intended to be sold within one year (or the normal operating cycle if longer) and may include trading securities, available-for-sale securities, or held-to-maturity securities (if maturing within one year), as applicable.

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Exercise price per share or per unit of warrants or rights outstanding.

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Amount of common stock allocated to investors to buy shares of a new issue of common stock before they are offered to the public. When stock is sold on a subscription basis, the issuer does not initially receive the total proceeds. In general, the issuer does not issue the shares to the investor until it receives the entire proceeds.

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For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

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The cash inflow from the issuance of common stock, preferred stock, treasury stock, stock options, and other types of equity.

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Cash received from licensees for license fees during the current period.

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The cumulative amount of the reporting entity's undistributed earnings or deficit.

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Amount, including tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value-added and excise.

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Per share amount received by subsidiary or equity investee for each share of common stock issued or sold in the stock transaction.

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Number of shares of stock issued as of the balance sheet date, including shares that had been issued and were previously outstanding but which are now held in the treasury.

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Per share or per unit amount of equity securities issued.

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Organization and Description of Business (Details) $ / shares in Units, $ in Thousands		1 Months Ended	9 Months Ended	12 Months Ended
	Aug. 13, 2018 $ / shares shares	Aug. 31, 2018 $ / shares shares	Sep. 30, 2019 USD ($) $ / shares shares	Dec. 31, 2018 USD ($) Number shares	Dec. 31, 2017 USD ($) shares	Jul. 16, 2019 $ / shares	Jun. 01, 2018 $ / shares shares	Nov. 30, 2017 $ / shares shares	Nov. 21, 2017 $ / shares shares	Dec. 08, 2016 $ / shares shares
Number of shares issued \| shares				7,021,092
Accumulated deficit \| $			$ (93,076)	$ (85,838)	$ (73,597)
Cash, cash equivalents and short-term investments \| $			$ 3,900	4,900
Exercise price (in dollars per share)			$ 1.6875
Common Stock Offering Warrants Issued \| shares			8,334
Proceeds from licensing fees \| $			$ 1,700	1,700
Proceeds from net product sales \| $			500	400
Proceeds from issuance and sale of common stock, preferred stock, warrants exercise, convertible and other promissory notes \| $			$ 67,200	$ 61,700
Right Offering [Member]
Exercise price (in dollars per share)	$ 23.00
Unit price (in dollars per unit)	$ 23.00
Number of subscriptions shares accept \| shares	267,853
Common Stock Offering Warrants Issued \| shares	267,853
Public Offering [Member]
Number of shares issued \| shares									293,000
Shares issued per share (in dollars per share)									$ 20.00
Exercise price (in dollars per share)									$ 1.00
Initial Public Offering [Member]
Number of shares issued \| shares										93,750
Exercise price (in dollars per share)						$ 33.75
Unit price (in dollars per unit)						$ 27.00
CommonStockPurchaseWarrantsMember \| Right Offering [Member]
Exercise price (in dollars per share)		$ 34.50
Common Stock Offering Warrants Issued \| shares		133,393
CommonStockPurchaseWarrantsMember \| Private placement [Member]
Number of shares issued \| shares							56,696	56,696
Exercise price (in dollars per share)							$ 36.40	$ 30.00
Warrant [Member] \| Initial Public Offering [Member]
Number of shares issued \| shares										9,375
Exercise price (in dollars per share)										$ 192.00
Investor [Member] \| Warrant [Member] \| Public Offering [Member]
Number of shares issued \| shares									233,775
Shares issued per share (in dollars per share)									$ 30.00
Roth Capital Partners, LLC [Member] \| Warrant [Member] \| Public Offering [Member]
Number of shares issued \| shares									47,250
Shares issued per share (in dollars per share)									$ 30.00
Accounts Receivable [Member]
Number of customers \| Number				1
Accounts Receivable [Member] \| Customer One [Member]
Percentage				91.00%
Customer Revenues \| $				$ 127
Sales Revenue, Net [Member]
Number of customers \| Number				2
Sales Revenue, Net [Member] \| Customer One [Member]
Percentage				52.00%
Customer Revenues \| $				$ 157
Sales Revenue, Net [Member] \| Customer Two [Member]
Percentage				13.00%
Customer Revenues \| $				$ 38