Stockholders' Equity And Stock-Based Compensation (Narrative) (Details)							1 Months Ended						3 Months Ended			6 Months Ended
	Jun. 09, 2022 USD ($) shares / item $ / shares shares	Jan. 01, 2022 shares	Jun. 30, 2021 USD ($) $ / shares shares	Feb. 25, 2021 $ / shares	Feb. 05, 2021 $ / shares shares	Feb. 04, 2021 USD ($) $ / shares shares	Jun. 30, 2022 $ / shares shares	Nov. 30, 2021 shares	Jul. 31, 2021 USD ($)	Mar. 31, 2021 shares	Feb. 28, 2021 USD ($)	Feb. 04, 2021 USD ($) $ / shares shares	Jun. 30, 2022 USD ($) $ / shares shares	Jun. 30, 2021 USD ($) $ / shares shares	Mar. 31, 2021 USD ($) shares	Jun. 30, 2022 USD ($) $ / shares shares	Jun. 30, 2021 USD ($) $ / shares shares	Dec. 31, 2021 $ / shares shares	May 31, 2021 shares	Jun. 30, 2020 $ / shares shares	Nov. 30, 2017 shares	Dec. 31, 2016 $ / shares shares	Dec. 31, 2014 $ / shares shares
Stockholders' Equity [Line Items]
Preferred stock, shares authorized							50,000,000						50,000,000			50,000,000		50,000,000
Preferred stock, par value | $ / shares							$ 0.001						$ 0.001			$ 0.001		$ 0.001
Preferred stock, shares outstanding							0						0			0		0
Common stock, shares authorized							500,000,000						500,000,000			500,000,000		500,000,000
Common stock, par value | $ / shares	$ 0.001						$ 0.001						$ 0.001			$ 0.001		$ 0.001
Proceeds from issuance of common stock | $																$ 14,963,000	$ 48,348,000
Common stock, shares issued							37,126,000						37,126,000			37,126,000		29,716,000
Total stock-based compensation expense | $													$ 1,713,000	$ 2,448,000		$ 3,720,000	$ 9,413,000
2017 Employee Stock Purchase Plan [Member]
Stockholders' Equity [Line Items]
Common stock, shares issued			85,844				85,844						85,844	85,844		85,844	85,844
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							563,252						563,252			563,252
2017 Inducement Equity Incentive Plan [Member]
Stockholders' Equity [Line Items]
Term period																10 years
Shares authorized																			1,000,000		1,000,000
Shares available for grant							793,139						793,139			793,139
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		1,188,657
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							2,271,900						2,271,900			2,271,900
Rights Offering [Member]
Stockholders' Equity [Line Items]
Price per share | $ / shares																				$ 7.01
Warrants/rights outstanding							0						0			0
Net proceeds | $												$ 4,500,000
Period the warrants are exercisable after issuance																30 days
Percentage requirement for warrant redemption																200.00%
Warrants exercised					5,139							636,432
Redemption per warrant | $ / shares				$ 0.01	$ 0.01
Period of time required for redemption of warrants																10 days
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 | $													$ 765,000	$ 946,000		$ 1,771,000	$ 2,984,000
Research and development [Member]
Stockholders' Equity [Line Items]
Total stock-based compensation expense | $													496,000	1,002,000		953,000	4,168,000
Options outstanding [Member]
Stockholders' Equity [Line Items]
Total stock-based compensation expense | $											$ 0				$ 4,200,000
Time-Based Options [Member]
Stockholders' Equity [Line Items]
Total stock-based compensation expense | $													1,445,000	1,917,000		$ 3,252,000	3,686,000
Time-Based Options [Member] | Tranche One Through Four [Member]
Stockholders' Equity [Line Items]
Vesting percentage																25.00%
Performance Shares [Member]
Stockholders' Equity [Line Items]
Total stock-based compensation expense | $													$ 132,000	$ 387,000		$ 215,000	$ 5,528,000
Private Placement [Member]
Stockholders' Equity [Line Items]
Common stock, par value | $ / shares																							$ 0.001
Warrants expired								600
2022 Rights Offering [Member]
Stockholders' Equity [Line Items]
Shares issued	7,317,072
Price per share | $ / shares	$ 2.05
Proceeds from issuance of common stock | $	$ 15,000,000
Additional proceeds that may be received upon exercise of warrants | $	$ 15,000,000
Warrants/rights outstanding	7,317,072						7,310,917						7,310,917			7,310,917
Exercise price of warrants/rights | $ / shares	$ 2.05
Warrant redemption price | $ / shares	$ 0.01
Number of shares per unit | shares / item	1
Number of warrants per unit	1
Number of shares per warrant | shares / item	1
Warrant redemption, notice period	30 days
Warrant redemption restrictions, stock price as percentage of exercise price	200.00%
Warrant redemption restrictions, number of consecutive trading days at which stock price must exceed exercise price	20 days
Warrant redemption restrictions, minimum period before redemption	3 months
Warrants exercised							6,155
Chairman, Robert W. Duggan [Member] | Private Placement [Member]
Stockholders' Equity [Line Items]
Shares issued			3,048,780
Common stock, par value | $ / shares			$ 0.001											$ 0.001			$ 0.001
Price per share | $ / shares			$ 16.40											$ 16.40			$ 16.40
Aggregate issuance costs | $			$ 41,000,000.0
Proceeds from issuance of common stock | $									$ 8,400,000
Directors [Member] | Private Placement [Member]
Stockholders' Equity [Line Items]
Proceeds from issuance of common stock | $									$ 8,400,000
Common Stock
Stockholders' Equity [Line Items]
Shares issued													7,317,000	131,000		7,317,000	288,000
Warrants exercised														5,000			45,000
Common Stock | Rights Offering [Member]
Stockholders' Equity [Line Items]
Warrants/rights outstanding																				641,571
Robert W. Duggan [Member] | Private Placement [Member]
Stockholders' Equity [Line Items]
Price per share | $ / shares			$ 16.40											$ 16.40			$ 16.40
MDB Capital Group, LLC [Member] | Initial Public Offering [Member]
Stockholders' Equity [Line Items]
Price per share | $ / shares																						$ 5.00
Warrants/rights outstanding							0						0			0
Number of common shares called by issuance of warrants																						574,985
Common stock received from rights/warrants exercised										68,958					68,958
Warrants exercised										85,385
Exercisable period of warrants or rights																5 years
MDB Capital Group, LLC [Member] | Private Placement [Member]
Stockholders' Equity [Line Items]
Price per share | $ / shares																							$ 2.67
Number of common shares called by issuance of warrants																							299,625
Common stock received from rights/warrants exercised										40,563					40,563
Warrants exercised										45,638
Exercisable period of warrants or rights																7 years
Stifel, Nicolaus & Company Inc. [Member] | At the Market Offering [Member]
Stockholders' Equity [Line Items]
Value of warrants/rights | $						$ 60,000,000.0						$ 60,000,000.0
Warrants/rights outstanding						288,490						288,490
Exercise price of warrants/rights | $ / shares						$ 27.73						$ 27.73
Net proceeds | $						$ 7,400,000