7. Stockholders’ Equity (Details Narrative) - USD ($)	1 Months Ended	6 Months Ended
	Aug. 31, 2019	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Class of Warrant or Right [Line Items]
Preferred stock, authorized (in shares)		10,000,000		10,000,000
Preferred stock, per value (in usd per share)		$ 0.001		$ 0.001
Preferred stock, outstanding (in shares)		0		0
Common stock, authorized (in shares)		240,000,000		120,000,000
Proceeds from exercise of warrants		$ 7,252,000
September 2020 Warrants [Member]
Class of Warrant or Right [Line Items]
Number of shares of common stock issued	6,648,750
Warrants exercisable as of June 30, 2021		960,000
August 232019 [Member]
Class of Warrant or Right [Line Items]
Number of shares of common stock issued	4,475,000
August 2019 Warrants [Member]
Class of Warrant or Right [Line Items]
Warrants exercisable as of June 30, 2021		900,000
September 2020 Warrants [Member]
Class of Warrant or Right [Line Items]
Warrant description		The September 2020 Warrants were initially exercisable for 6,648,750 shares of common stock at an exercise price per share equal to $0.84. The September 2020 Warrants became exercisable beginning on March 9, 2021 and will expire on March 9, 2026.
Class of Warrant or Right, Exercise Price of Warrants or Rights		$ 0.84
Date on which warrants became exercisable		Mar. 09, 2021
Number of warrants exercised		5,600,000
Proceeds from exercise of warrants		$ 4,700,000
August 2019 Warrants [Member]
Class of Warrant or Right [Line Items]
Warrant description		On August 23, 2019, the Company entered into a securities purchase agreement with certain institutional investors pursuant to which the Company issued and sold an aggregate of 4,475,000 shares of common stock in a registered direct offering and issued warrants to purchase up to 2,237,500 shares of common stock in a concurrent private placement (the “August 2019 Warrants”). The August 2019 Warrants were initially exercisable for 2,237,500 shares of common stock at an exercise price per share equal to $1.78. The August 2019 Warrants became exercisable beginning on February 27, 2020 and will expire on August 28, 2023.
Class of Warrant or Right, Exercise Price of Warrants or Rights		$ 1.78
Date on which warrants became exercisable		Feb. 27, 2020
Number of warrants exercised		1,300,000
Proceeds from exercise of warrants		$ 2,400,000
Series A Warrants [Member]
Class of Warrant or Right [Line Items]
Warrant description		The Series A Warrants were initially exercisable for 1,463,519 shares of common stock at an exercise price per share equal to $4.15, which was adjusted several times pursuant to the terms thereof to 3,629,023 shares of common stock at an exercise price per share equal to $0.2957 per share. The most recent adjustment to the exercise price (from $0.60 to $0.2957 per share) occurred during the three months ended September 30, 2020 as a result of the announcement of the offerings pursuant to the 2020 Securities Purchase Agreement. The Series A Warrants were immediately exercisable upon issuance and will expire on January 31, 2024.
Class of Warrant or Right, Exercise Price of Warrants or Rights		$ 0.2957
Number of warrants exercised		500,000	0
Proceeds from exercise of warrants		$ 100,000	$ 0
Warrants exercisable as of June 30, 2021		300,000