Condensed Consolidated Balance Sheets - USD ($)	Jun. 30, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 21,014,375	$ 7,619,748
Short-term investments available-for-sale, at fair value	11,852,173	25,410,222
Restricted cash		3,270,247
Accounts receivable	1,011,462	3,164,176
Inventory, net of allowance of $29,587 at June 30, 2020 and $39,403 at December 31, 2019	1,388,570	1,269,667
Prepaid expenses and other	1,236,192	633,522
Total current assets	36,502,772	41,367,582
Operating lease right-of-use assets	905,459	1,209,145
Property and equipment, net	1,825,191	2,240,133
Other non-current assets	69,365	302,409
Total assets	39,302,787	45,119,269
Current liabilities:
Accounts payable	927,829	1,662,583
Accrued liabilities	947,382	1,870,296
Contract liabilities - current	418,874	426,014
NuvoGen obligation - current	863,611	1,152,233
Short-term debt, net	1,143,011	2,987,667
Operating lease liabilities - current	584,073	758,932
Other current liabilities	30,983	41,134
Total current liabilities	4,915,763	8,898,859
NuvoGen obligation - non-current, net of discount	4,359,218	4,498,777
Long-term debt, net	10,705,219	6,871,545
Operating lease liabilities - non-current	453,404	636,340
Other non-current liabilities	185,276	244,114
Total liabilities	20,618,880	21,149,635
Commitments and Contingencies (Note 15)
Stockholders’ equity:
Series A convertible preferred stock, $0.001 par value; 51,270 shares authorized at June 30, 2020 and no shares authorized at December 31, 2019; 23,770 shares issued and outstanding at June 30, 2020 and no shares issued and outstanding at December 31, 2019	24
Common stock, $0.001 par value; 200,000,000 shares authorized at June 30, 2020 and December 31, 2019, 67,093,683 shares issued and outstanding at June 30, 2020 and 58,090,233 shares issued and outstanding at December 31, 2019	67,093	58,090
Additional paid-in-capital	200,079,879	194,234,151
Accumulated other comprehensive income (loss)	23,003	(4,964)
Accumulated deficit	(181,486,092)	(170,317,643)
Total stockholders’ equity	18,683,907	23,969,634
Total liabilities and stockholders' equity	$ 39,302,787	$ 45,119,269