Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Current assets
Cash and cash equivalents	$ 98,707	$ 107,704
Marketable securities	55,573	67,576
Accounts receivable, net	30,365	30,025
Inventories	12,676	15,394
Prepaid expenses and other current assets	7,301	5,112
Total current assets	204,622	225,811
Property and equipment, net	19,610	19,538
Right-of-use assets	6,147	6,577
Total assets	230,379	251,926
Current liabilities
Accounts payable	6,650	6,928
Accrued expenses and other current liabilities	21,453	20,008
Deferred revenue	10,000	10,000
Operating lease liabilities	1,546	1,526
Current portion of long-term debt	18,333	16,806
Total current liabilities	57,982	55,268
Long-term operating lease liability, net	5,746	6,123
Long-term debt, net	39,758	44,114
2024 convertible notes, net	165,271	162,786
Other long-term liabilities	489	295
Total liabilities	269,246	268,586
Commitments and contingencies
Preferred stock, $0.001 par value; 10,000,000 shares authorized at March 31, 2021 and December 31, 2020 and 0 shares issued and outstanding at March 31, 2021 and December 31, 2020	0	0
Stockholders' deficit
Common stock, $0.001 par value; 100,000,000 shares authorized; 49,941,553 and 49,403,034 shares issued and outstanding, at March 31, 2021 and December 31, 2020, respectively	50	49
Additional paid-in capital	771,954	765,607
Accumulated other comprehensive loss	(10)	(11)
Accumulated deficit	(810,861)	(782,305)
Total stockholders' deficit	(38,867)	(16,660)
Total liabilities and stockholders' deficit	$ 230,379	$ 251,926