Stockholders' Equity And Stock-Based Compensation (Narrative) (Details) - USD ($)			3 Months Ended				6 Months Ended		18 Months Ended
	Jan. 01, 2019	Dec. 06, 2018	Jun. 30, 2019	Jun. 30, 2018	Sep. 30, 2017	Jun. 30, 2017	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Dec. 31, 2018	Oct. 25, 2018	Nov. 30, 2017	Dec. 31, 2016	Dec. 31, 2014
Stockholders' Equity [Line Items]
Common stock, par value			$ 0.001				$ 0.001		$ 0.001	$ 0.001
Common stock, shares issued			20,768,000				20,768,000		20,768,000	20,593,000
Total stock-based compensation expense			$ 2,699,000	$ 3,175,000			$ 5,060,000	$ 6,595,000
Cash received from option exercises							$ 272,000	164,000
2017 Employee Stock Purchase Plan [Member]
Stockholders' Equity [Line Items]
Common stock, shares issued			18,574				18,574		18,574
Shares authorized			250,000				250,000		250,000
Increase in shares available for issuance threshold of common stock outstanding, number of shares							450,000
Increase in shares available for issuance threshold of common stock outstanding, percent outstanding							1.50%
Shares available for grant			459,900				459,900		459,900
2017 Inducement Equity Incentive Plan [Member]
Stockholders' Equity [Line Items]
Term period							10 years
Shares authorized												1,000,000
Shares available for grant			364,750				364,750		364,750
2017 Plan [Member]
Stockholders' Equity [Line Items]
Term period							10 years
Shares authorized			1,500,000				1,500,000		1,500,000
Additional common stock reserved for issuance	823,716
Increase in shares available for issuance threshold of common stock outstanding, number of shares							1,200,000
Increase in shares available for issuance threshold of common stock outstanding, percent outstanding							4.00%
Shares available for grant			1,289,371				1,289,371		1,289,371
First Vesting Portion [Member] | 2017 Inducement Equity Incentive Plan [Member]
Stockholders' Equity [Line Items]
Vesting percentage							25.00%
Sales, general and administrative [Member]
Stockholders' Equity [Line Items]
Total stock-based compensation expense			$ 1,660,000	2,351,000			$ 3,145,000	5,050,000
Research and development [Member]
Stockholders' Equity [Line Items]
Total stock-based compensation expense			$ 1,039,000	824,000			$ 1,915,000	1,545,000
Options outstanding [Member]
Stockholders' Equity [Line Items]
Options granted							487,932
Warrants exercised							98,928
Exercise price			$ 16.11				$ 16.11		$ 16.11
Restricted Stock Units [Member]
Stockholders' Equity [Line Items]
Shares issued			40,582
Reduction to APIC from shares withheld for tax			$ 400,000			$ 100,000
Total stock-based compensation expense			$ 0	900,000			$ 0
Performance Shares [Member]
Stockholders' Equity [Line Items]
Options granted			31,875
Officer [Member] | Restricted Stock Units [Member]
Stockholders' Equity [Line Items]
Units granted during period						160,974
Total stock-based compensation expense								$ 2,100,000
Certain Employees [Member] | Restricted Stock Units [Member]
Stockholders' Equity [Line Items]
Shares issued			17,456
Units granted during period					68,800
Reduction to APIC from shares withheld for tax			$ 200,000
Total stock-based compensation expense			$ 100,000	$ 100,000			$ 200,000		$ 200,000
Certain Employees [Member] | Restricted Stock Units [Member] | First Vesting Portion [Member]
Stockholders' Equity [Line Items]
Vesting percentage					50.00%
Cliff vest date							Jun. 01, 2019
Certain Employees [Member] | Restricted Stock Units [Member] | Second Vesting Portion (Per Month) [Member]
Stockholders' Equity [Line Items]
Vesting percentage					50.00%
Cliff vest date							Jun. 01, 2021
Certain Employees [Member] | Restricted Stock Units [Member] | Change In Control [Member]
Stockholders' Equity [Line Items]
Vesting percentage					100.00%
Common Stock
Stockholders' Equity [Line Items]
Warrants exercised				17,000			99,000	55,000
Common Stock | Rights Offering [Member]
Stockholders' Equity [Line Items]
Net proceeds		$ 44,800,000
Right entitlement to holder		3,581,148									0.19860755
Exercise price of warrants/rights											$ 12.57
Common Stock | Chairman, Robert W. Duggan [Member] | Rights Offering [Member]
Stockholders' Equity [Line Items]
Ownership percentage		35.00%
Shares purchased		3,146,226
Investment		$ 39,500,000
MDB Capital Group, LLC [Member] | Initial Public Offering [Member]
Stockholders' Equity [Line Items]
Price per share													$ 5.00
Warrants/rights outstanding			121,609				121,609		121,609
Exercisable period of warrants or rights							5 years
Number of common shares called by issuance of warrants													574,985
MDB Capital Group, LLC [Member] | Private Placement [Member]
Stockholders' Equity [Line Items]
Price per share														$ 2.67
Warrants/rights outstanding			91,876				91,876		91,876
Exercisable period of warrants or rights							7 years
Number of common shares called by issuance of warrants														299,625