CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 7,118	$ 3,084
Short-term investments	46,862	57,704
Receivables, net	24,117	35,185
Inventory	1,211	1,147
Prepaid expense and other assets	6,303	6,625
Total current assets	85,611	103,745
Property and equipment, net	3,355	3,829
Right of use assets	27,081	27,082
Restricted investments	1,154	1,154
Advanced payments, non-current	1,013	1,159
Total assets	118,214	136,969
Liabilities and shareholders' deficit
Accounts payable	12,960	5,328
Accrued expenses	41,379	46,627
Current portion of lease liabilities	3,597	3,504
Total current liabilities	57,936	55,459
Lease liabilities, non-current	31,396	32,318
Unsecured convertible senior notes, net	160,746	158,213
Commitments and contingencies (Note 8)
Shareholders' deficit:
Preferred stock, par value $0.01 per share, 20,000,000 shares authorized; none issued and outstanding at March 31, 2020 and December 31, 2019.
Common stock, par value $0.01 per share, 150,000,000 shares authorized at March 31, 2020 and December 31, 2019; 54,507,667 and 54,200,810 shares issued and outstanding at March 31, 2020 and December 31, 2019, respectively.	545	542
Additional paid-in capital	631,233	625,048
Accumulated deficit	(763,642)	(734,611)
Total shareholders' deficit	(131,864)	(109,021)
Total liabilities and shareholders' deficit	$ 118,214	$ 136,969