CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 28, 2019
Current assets:
Cash and cash equivalents	$ 21,397	$ 20,092
Marketable securities	111,317	60,596
Accounts receivable	6,141	6,559
Inventory	12,984	11,216
Prepaid expenses and other current assets	2,287	1,538
Total current assets	154,126	100,001
Property and equipment, net	4,690	4,792
Restricted cash	500	500
Other long-term assets	6	6
Total assets	159,322	105,299
Current liabilities:
Accounts payable	778	7,247
Accrued expenses and other current liabilities	11,474	8,332
Deferred revenue	1,347	166
Current portion of deferred rent	25	370
Total current liabilities	13,624	16,115
Long-term debt, net of discount and current portion	34,525	34,146
Deferred rent, net of current portion	1,623	389
Total liabilities	49,772	50,650
Commitments and contingencies (Note 10)
Stockholders' equity:
Preferred stock, no par value; 25,000,000 shares authorized; no shares issued or outstanding
Common stock, no par value; 150,000,000 shares authorized; 27,159,065 shares and 21,184,524 shares issued and outstanding at September 30, 2020 and December 28, 2019, respectively	501,486	424,134
Accumulated other comprehensive loss	(16)	(2)
Accumulated deficit	(391,920)	(369,483)
Total stockholders' equity	109,550	54,649
Total liabilities and stockholders' equity	$ 159,322	$ 105,299